An 11-time Pro Bowl selection, Allen played 12 seasons with the Cowboys and earned a Super Bowl ring with the team after a 27-17 win over the Pittsburgh Steelers in Super Bowl XXX. He played his final two seasons with the San Francisco 49ers before signing a one-day contract with the Dallas Cowboys, allowing him to retire with the organization that drafted him, prior to the 2008 regular season. In his career, he played in more Pro Bowls than any other Dallas Cowboys offensive player, in franchise history.
At 6-feet 3-inches tall and weighing 325 pounds, Allen is regarded as possibly one of the physically strongest men to have ever played in the NFL with an unwitnessed 900lb-plus squat and deadlift as well as a three-person assisted bench press of 700lbs-plus.
Allen was forced into starting just four games into his rookie season when Mark Tuinei suffered back spasms on the road against the Washington Redskins. He received the game ball for helping keep the Redskins sackless for the game. He recorded his first NFL start at left tackle, replacing an injuried (Mark) Tuinei against the Arizona Cardinals. This marked the first time a rookie offensive lineman had started for Dallas since November 24, 1991 when Erik Williams started at right tackle against the Redskins. Allen returned to a back-up role for the next two weeks, but early in the morning on October 24, (Erik) Williams was injured in automobile accident and was out for the rest of the season. After which, Allen was moved into the starting line-up at (Erik) Williams’s right tackle position permanently beginning at the Cincinnati Bengals on October 30). He received game ball, along with (Mark) Tuinei, for helping hold the New Orleans Saints without a sack in a Monday night win in New Orleans on December 19. In his first playoffs, Allen received the game ball against the Green Bay Packers on January 8, when the Dallas offense recorded 450 total yards and Troy Aikman completed 23-of-30 passes for 337 yards. Allen sprained his left ankle during the game, however he returned to play. In the NFC Championship Game at San Francisco 49ers, he struggled playing through three quarters on his injured ankle before leaving the game.
In 1995, Allen, while earning his first of seven consecutive trips to the Pro Bowl, was one of a club-record four Dallas offensive linemen named to the Pro Bowl, Ray Donaldson, Nate Newton, and Mark Tuinei being the others, after just one year of experience as a starting guard. The team finished fifth in the league in total offense while Emmit Smith gained a franchise record 1,773 rushing yards, his fourth NFL rushing title in five years and scored, a then, NFL record 25 rushing touchdowns.
Allen made first NFL start at right guard in the season opener at the Meadowlands against the New York Giants on September 4, helping the Dallas offense record 459 yards including 230 rushing yards. In the regular-season finale on the road against the Cardinals on Christmas Day, the offensive line enabled Dallas to record 474 yards of total offense for most yardage by Cowboys team since September 15, 1985. On January 28, 1996, Allen earned his first start in a Super Bowl as well as his first and only Super Bowl ring when the Cowboys defeated the Pittsburgh Steelers 27-17 in Super Bowl XXX.
In 1996, Allen earned a second consecutive trip to the Pro Bowl, along with earning consensus All-Pro and All-NFC honors. The Dallas offensive line led league by allowing just 19 sacks, one shy of the team record set the previous year. For the third consecutive season behind Allen, Emmit Smith ran for over 1,200 yards while passing 100 rushing yards four times, including a season-high 155 yards and three touchdowns against the Redskins on Noveber 28.
In 1997, Allen, despite being moved between guard and tackle during the season, was selected to his third consecutive Pro Bowl at guard and earned first-team All-Pro honors. He also spent part of training camp working at left tackle and returned to his right guard position for the first 13 games of season.
He started his third season at right guard at Pittsburgh and helped Dallas gain 380 total yards, including 295 passing yards while not allowing a sack. He left the September 15 win over the Philadelphia Eagles after suffering a strained left hamstring in the second quarter and did not return. He returned to the starting lineup following the bye week against the Chicago Bears on September 28, but was forced to leave in the second quarter without enough strength in his left leg to block effectively. He was once again back in the starting lineup the following week at the Giants. He was then forced to move out to left tackle after the loss of Mark Tuinei in Washington on October 13. Allen remained at left tackle in third down passing situations against the Eagles and Redskins on October 26 and November 16. He became a full-time starter at left tackle against the upstart Carolina Panthers on December 8, and remained there the final three weeks of the season.
In 1998, Allen was slated to start at the left tackle position from day one of the season after starting final three games of 1997 at left tackle. In his first full season guarding Troy Aikman’s blindside, he earned consensus All-Pro and All-NFC honors. He became just the third player in league history to be selected to the Pro Bowl at more than one offensive line position when peers voted him to NFC Pro Bowl team at tackle. He earned recognition as part of an offensive line that allowed just 19 sacks for 110 yards in 493 pass plays for season, the fewest in NFL. His blocking helped Emmit Smith to record seven 100-yard rushing games and 1,332 yards on the season.
He debuted at his new position in the season opener against the Arizona Cardinals and helped Dallas gain 444 total yards (188 rushing), both totals were the teams highest since 1996. He helped lead way as two running backs topped 100-yard mark for just the third time in franchise history at Washington on October 4, (Emmit) Smith finished with 120 yards and one touchdown while Chris Warren recorded 104 yards and two touchdowns. In November, he faced four of the NFC’s top defensive ends in Hugh Douglas, Chad Bratzke, Simeon Rice, and John Randle. Allen's streak started at Philadelphia on Nobember 2, when he limited (Hugh) Douglas to one tackle and no sacks. The following week against the Giants and (Chad) Bratzke, his blocking helped Emmit Smith rush for 163 yards on 29 carries, a 5.6 avg. The Dallas offensive line allowed no sacks to the Giants defense that led NFL in sacks in 1998. In Arizona, Allen limited (Simeon) Rice to one tackle and was part of an offensive line that allowed no sacks to the Cardinals defense as well. He led the way for (Emmit) Smith’s 118 rushing yards and three touchdowns. The Seattle Seahawks had the AFC’s top sacking defense of 1998 (11 sacks for 22 yards) and came away with just one sack (on an (Troy) Aikman fumble), while the Cowboys ran for 173 yards. He also limited (John) Randle to one tackle and no sacks in 81 offensive plays against the Minnesota Vikings on Novebmer 26. He also helped set a new franchise record for pass attempts in a game without a sack (57) and led the way as (Emmit) Smith rushed for three touchdowns to tie Marcus Allen’s NFL record of 123 career rushing touchdowns. In the regular season finale against the Redskins on December 27, Allen was part of an offensive line that saw Smith run for two more touchdowns to break NFL’s all-time rushing touchdown record.
In 1999, despite starting in his third offensive line position in as many years and missing five games due to injury, Allen was selected to his fifth consecutive Pro Bowl while earning consensus All-Pro honors at guard.
Allen earned recognition as part of an offensive line that allowed the second-fewest sacks (24) in the league, behind Indianapolis who allowed just 14, and one-or-fewer sacks in nine-of-16 games. He helped lead the way as the Cowboys gained 541 total yards while giving up only one sack in 50 pass plays in first career start at left guard at Washington on September 12. He helped lead the way as Emmit Smith became just third player in last 29 games to rush for over 100 yards against the Atlanta Falcons on Setember 20, when he rushed for 109 yards. Allen's blocking helped the Cowboys offensive line allow only one sack in 40 pass plays in Philadelphia on October 10. He gave up no sacks on 32 pass plays, to the Redskins on October 24. His blocking helped Smith to rush for 140 yards and two touchdowns in the first half as the Dallas offense recorded 205 rushing yards in Minnesota on November 8. Allen helped the Cowboys running backs record 149 yards before leaving game in third quarter with sprained medial collateral ligament (MCL) in his right knee against the Packers on November 14. He missed the his first career game in Arizona on November 21, snapping strings of 97 consecutive games played and 90 consecutive starts. He missed the next four games with a sprained knee. He returned to the starting lineup in New Orleans on Christmas Eve and helped the Cowboys offensive line give up no sacks on 39 pass plays while helping (Emmit) Smith to rush for his eighth 100-yard game of the season. In the season finale against the Giants on New Years Day, he helped block for (Emmit) Smith as he recorded his ninth 100-yard game of the season. Allen was also part of an offensive line that did not allow a sack in 33 pass plays during the game. In the NFC Wild Card Playoff Game in Minnesota on January 9, he opened holes for (Emmit) Smith to rush for 99 yards, including a Dallas postseason record 65-yarder.
Despite suffering a fractured right hand in practice on June 20, Allen returned to play by the end of the preseason and started all 16 games. His blocking helped limit the Cardinals to one sack while protecting Randall Cunningham as he completed 24-of-34 passes for 243 yards and three touchdowns on September 10. His blocking against Arizona on October 22 was key to the offense as it recorded 347 total yards, including 200 rushing yards. He allowed just one sack. He helped limit Warren Sapp to two tackles for the game in Tampa Bay, on December 3, while the entire Tampa Bay starting defensive line was limited to six tackles. He was also part of an offensive line that helped (Emmit) Smith rush for 150 yards and a touchdown against the Redskins and the NFL’s fourth ranked defense on December 10. The Cowboys rushed for 242 yards against the Redskins for most by Dallas offense since recording 271 rushing yards in Philadelphia on Halloween 1993.
In 2001, Allen was named All-Pro by the Associated Press for the seventh consecutive season. He was also named a Pro Bowl starter at guard. However, he was unable to attend the game in Hawaii due to elbow surgery that was performed after the season ended. Marked seventh consecutive Pro Bowl selection.
Allen played a key role in Dallas’ third rank in the league in rushing at 136.5 yards-per-game. The season rushing total of 2,184 yards was the second-best total by a Cowboys team in last 20 years (1995, 2,201). He helped limit All-Pro DT (Warren) Sapp to one tackle and no sacks in the season opener against the Buccaneers, also helping the Cowboys offense rush for 99 yards on 23 carries, a 4.3 average. He led the way for Emmit Smith to his first 100-yard rushing game of the season, 107 yards, and offense to 211 total rushing yards in the Cowboys Monday night win over the Redskins on October 15. He played a part in helping Troy Hambrick gain 127 rushing yards as well as Michael Wiley gain 85 en route to the Cowboys gaining 207 rushing yards (6.3 avg.) at Atlanta on November 11. He played a key role in Dallas' 20-14 win over the Redskins on December 2, as the Cowboys recorded their third 200-plus yard rushing game of the season as the team rushed the ball 44 times for 215 yards, a 4.9 average, including 102 yards by (Emmit) Smith.
In 2002, Allen had a challenging season due to injuries. He played through off-season surgery and a nagging early season ankle sprain that limited him to five starts on the season between left guard and right tackle. Due to his off-season rotator cuff surgery on his left shoulder, and was limited in training camp and played in just the final two preseason games. He was selected as an offensive capitain by his teammates, entering the regular season.
Allen sprained his left ankle in the second quarter against the Tennessee Titans on September 15. He attempted to return in the second half but lasted just two plays before returning to the sideline. He was inactive at Philadelphia on September 22, due to his ankle injury. He moved to right tackle during practice the week leading up to St. Louis Rams game on September 29, and opened the game at that position before re-aggravating his sprained left ankle. He then left the game in the first quarter. He returned to the starting lineup at right tackle against the New York Giants on October 6, but came out during first drive after aggravating left ankle. He fought the pain and was in and out of the game in the second half at left guard for Kelvin Garmon who suffered a hip injury. Following trade of (Kelvin) Garmon to the Chargers, Allen returned to left guard against the Panthers on October 13, but left the game in the second quarter with an ankle pain. He was then inactive next the three games to let the injury heal. He returned to practice the week against the Colts on November 17. but was inactive for a fourth straight game. He was placed on injured reserve on November 21, and underwent successful surgery on December 3, to remove bone spurs from left ankle.
In 2003, Allen returned after missing most of the 2002 season with a sprained left ankle that required off-season surgery to remove bone spurs. He returned and started all 16 regular season games and the playoff game at Carolina on January 3. Despite missing parts of four games with injuries, he returned and was honored for play with eighth Pro Bowl selection at guard.
He began the season by straining his hamstring during practice four days before the season opener. However he still started against the Falcons, but aggravated his hamstring in the second quarter and sat out remainder of half before coming back for the second half as offense recorded 403 total yards. He played at the New York Giants on September 15, and helped protect Quincy Carter, allowing him to throw for 321 yards in leading Dallas to a come-from-behind overtime win. He suffered a sprained left knee in the second quarter against the Cardinals on October 5, but returned in the second half to help Dallas total 365 yards of offense. Despite playing sporadically against the Washington on November 2, due to a sprained left knee suffered in the first quarter, he helped the Cowboys record 400 yards of total offense, including 208 rushing yards. All also helped hold DT Kris Jenkins to zero sacks, while the Dallas line allowed only one sack for zero yards in 45 pass plays against the Panthers on November 23. He also helped lead way for Troy Hambrick to run for 189 yards agaisnt the Redskins on December 14.
In the season opener in Minnesota, Allen’s blocking helped the Cowboys offense record 423 yards of total offense. In the home opening win over the Cleveland Browns on September 19, the Cowboys recorded a season-high 441 total yards, and Vinny Testaverde passed for 322 yards with only one sack in 36 passes. The Cowboys also rushed for 126 yards. He helped the Cowboys record 166 rushing yards for the game against the Giants on October 10. On Thanksgiving Day, in a win over Chicago, he was part of a line that led the way for Julius Jones to rush for 150 yards. In a Monday night win at Seattle on December 6, the Cowboys offensive line’s blocking opened holes for (Julius) Jones to run for 198 yards, the third best rushing game in franchise history and the second best ever by a Cowboys rookie. In the season finale loss at the Giants, the Cowboys offensive line ended the season by opening holes for (Julius) Jones to rush the ball 29 times for 149 yards a 5.1 average and a touchdown.
He started his 11th season as a full-time starter and his seventh consecutive season opener at left guard at San Diego on September 11. He helped the Cowoys offense record 28 points and 301 yards of total offense. He started against the Eagles on October 9, and helped the Cowboys offense recoed a season-high 456 yards of total offense. His blocking helped protect Drew Bledsoe and allowed him to complete 26-of-37 passes for 312 yards against the Giants on October 16. Allen helped the Cowboys running backs record 164 yards averageing 4.2 yard-per-carry in Seattle on October 23. He helped lead way as Marion Barber III rushed for 127 yards and two touchdowns on 27 carries against the Cardinals on October 30. He was part of an offensive line that allowed (Drew) Bledsoe time to throw for 332 yards and three touchdowns while the running backs recorded 129 yards and a touchdown against the Kansas City Chiefs on Deceber 11, the 445 yards of total offense was the second-best of the season. His run blocking allowed Julius Jones to rush for 194 yards, the fourth best performance in franchise history in Carolina on Christmas Eve. The Cowboys offense recorded 22 first downs, 394 total yards, including a season-high 214 rushing, and 24 points in the come-from-behind win. During the Pro Bowl weekend in Honolulu, Hawaii, he won ESPN's "Strongest Man Award" during the Pro Bowl weekend in 2006 by bench pressing 43 reps with 225 pounds.
On March 21, 2006, Allen was released by the Dallas Cowboys, after spending his first 11 seasons with the organization.
Allen started at left guard, but left the game due to a sprained medial collateral ligament (MCL) injury suffered in the first quarter in Arizona on September 10, and was replaced by Tony Wragge. He was then inactive for the next five weeks due to a sprained medial collateral ligament (MCL) suffered in Arizona. He returned to the starting lineup in Chicago on October 29. The entire offensive line was awarded game balls by Head Coach Mike Nolan, in part for their job blocking for the runnig back who rushed for for 198 rushing yards against the Lions on November 12. He started at left guard against the Seahawks on November 19, and played with an offensive line that blocked for (Frank) Gore’s single-game franchise record 212 rushing yards. The 49ers accumulated 262 total rushing yards in the game, the eighth most in franchise history. The last time they rushed for that many yards was against Detroit on December 14, 1998, when they ran for a then-franchise-record 328 yards. (Frank) Gore, who was awarded a game ball by (Mike) Nolan, in turn gave game balls to the entire offensive line. Allen started at left guard in Seattle on December 14, in one of the best offensive line performances of the season, QB Alex Smith was not sacked once and the 49ers ran for 228 yards, of which, 144 yards where by (Frank) Gore’s. Allen was named as a reserve guard for the NFC in the Pro Bowl during the game week to mark his 11th Pro Bowl selection. He started in Denver on New Years Eve and blocked for (Frank) Gore to break the 49ers franchise's single-season rushing record and franchise combined yardage record (2,180). During the Pro Bowl weekend he successfully defended his ESPN's "Strongest Man Award" title at the 2007 Pro Bowl.
He is also married to his wife, Janelle. And they have two daughters, Jayla and Loriana, and one son, Larry, Jr.