Christensen was born in Pennsylvania while his father was working on a doctorate degree at Penn State University. After teaching in West Virginia, his father was offered a professorship in Eugene, Ore., when Todd was 5 and the family relocated.
Athletically, Christensen’s early desire was to continue excelling in track and field as he had when he set the world records as a 9-year-old boy. “Puberty and adolescence helped me realize that I was not as fast as I had thought,” he recalled. “My body went a different direction and that was when I started leaning towards football.”
He graduated from Sheldon High School (Eugene, Oregon).
At BYU, Christensen was a four-year starter (1974-77) at running back, led the team for three consecutive seasons in receiving and was an All-Western Athletic Conference selection in 1977. His career numbers while at BYU: 152 receptions, 1,568 yards and 15 touchdowns. He graduated with a degree in social work in 1978 before embarking on his pro career.
After three seasons of unspectacular statistics (including the Raiders' Super Bowl winning campaign in 1980), Christensen broke out in 1982, catching 42 balls for 510 yards and 4 TD's in the strike-shortened season, helping the Raiders to the best record in the NFL.
The next year, Christensen caught 92 passes for a career high 1,247 yards and 12 touchdowns and earned the first of his five trips to the Pro Bowl for his efforts. His total catches led the NFL, making him the second tight end to ever do this (Kellen Winslow was the other).
Christensen topped 1,000 yards again in 1984, catching 82 passes in the process. He hit 80 receptions again the following year, missing 1,000 yards by just 13 yards.
The 1986 NFL season was Christensen's last big one statistically. He ended the year with a career-high, league-leading 95 receptions for 1,153 yards and 8 touchdowns. He also became the first tight end in history to catch 90 passes in two seasons.
Christensen's 1987 campaign was cut short, but in 12 games he still managed to catch 47 balls (a little less than 4 a game). His 663 yards averaged to 14.1 yards per reception, a career high in seasons where he caught at least 40.
In Christensen's final year, he missed more than half the season with injuries and only managed 15 receptions, with none going for touchdowns.
In his career, Christensen caught 461 passes for 5,872 yards and 41 touchdowns. In eight postseason games, he caught 31 balls for 358 yards and only one touchdown.
After retiring from football, Christensen got into TV work, co-hosting the second half of the first season of American Gladiators with Mike Adamle. He later joined the NFL on NBC and has recently done color commentary for ESPN's college football coverage before moving into his current position.