During his 17-year career spent with the Giants, Milwaukee & Atlanta Braves, Oakland Athletics, New York Yankees, Montreal Expos, and Milwaukee Brewers, Alou played all three outfield positions regularly (736 games in right field, 483 in center, 433 in left), and led the National League in hits twice and runs once. Batting regularly in the leadoff spot, he hit a home run to begin a game on 20 occasions. He later became the winningest manager in Expos history, leading the team from 1992 to 2001 before rejoining the Giants in 2003.
Alou made his major league debut in and was an All-Star in , when he batted .316 with 25 home runs and 98 RBI.
Alou was joined by his brothers, Matty in , and Jesus in , who became the first all-brother outfield.
Alou was traded to the Braves before . Two years later he enjoyed his best season, when he batted .327 with 31 home runs and led the league in runs (122), hits (218), at bats (666), and total bases (355); he finished second in the batting race to his brother Matty. He also had a good year in , batting .317 and leading the league in hits (210) and at bats (662); he made the All-Star team both years. Alou continued to play with several more teams through , though he never again approached this level of success.
After the end of his playing career, Alou joined the Montreal Expos organization in 1976, becoming a batting coach and a minor league manager. The Giants offered him the manager's spot in , but he remained with the Expos out of loyalty. On May 22, , Alou was promoted from the Expos bench coach to field manager, becoming the first Dominican-born manager in MLB history. The team was developing a core of young talent during this period, including Larry Walker, John Wetteland, Delino DeShields, and Alou's own son, Moisés. In the Expos had the best record in the major leagues; however, the strike that year denied the Expos a chance at getting to their first World Series, and ownership soon began dealing all their young talent to cut payroll. Alou was named the NL Manager of the Year. The Los Angeles Dodgers tried to lure him away in , but he declined to leave Montreal. Eventually, Alou became the winningest manager in team history.
Despite Alou's popularity in Montreal, the Expos' dismal record eventually led to his dismissal by new owner Jeffrey Loria, who replaced him with Jeff Torborg during the season. Several teams tried to lure Alou out of retirement, including the Boston Red Sox, but he would not budge. He finally agreed to serve a single year as the bench coach for Detroit Tigers rookie manager Luis Pujols (). Prior to the season, Alou was named manager of the Giants, the team where he began his professional baseball career, replacing Dusty Baker who had left to manage the Chicago Cubs. In his first season in San Francisco, he managed his team into the playoffs, where they were defeated by the Florida Marlins in the NL Division Series in 4 games. The Marlins went on to win the World Series.
In , the Giants signed Moisés Alou to a one-year contract with an option for the season, reuniting him professionally with his father after seven seasons apart.
| Team | Year | Regular Season | Post Season | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Won | Lost | Win % | Finish | Won | Lost | Win % | Result | ||
| MON | 1992 | 70 | 55 | .560 | 2nd in NL East | - | - | - | - |
| MON | 1993 | 94 | 68 | .580 | 2nd in NL East | - | - | - | - |
| MON | 1994 | 74 | 40 | .649 | 1st in NL East | - | - | - | - |
| MON | 1995 | 66 | 78 | .458 | 5th in NL East | - | - | - | - |
| MON | 1996 | 88 | 74 | .543 | 2nd in NL East | - | - | - | - |
| MON | 1997 | 78 | 84 | .481 | 4th in NL East | - | - | - | - |
| MON | 1998 | 65 | 97 | .401 | 4th in NL East | - | - | - | - |
| MON | 1999 | 68 | 94 | .420 | 4th in NL East | - | - | - | - |
| MON | 2000 | 67 | 95 | .414 | 4nd in NL East | - | - | - | - |
| MON | 2001 | 21 | 32 | .396 | 5th in NL East | - | - | - | - |
| SFG | 2003 | 100 | 61 | .621 | 1st in NL West | 1 | 3 | .250 | Lost to Florida Marlins |
| SFG | 2004 | 91 | 71 | .562 | 2nd in NL West | - | - | - | - |
| SFG | 2005 | 75 | 87 | .463 | 3rd in NL West | - | - | - | - |
| SFG | 2006 | 76 | 85 | .472 | 3rd in NL West | - | - | - | - |
| Total | 1033 | 1021 | .503 | 1 | 3 | .250 | - | ||