He played in MLB for the Pittsburgh Pirates, Montreal Expos, Florida Marlins, Houston Astros, Chicago Cubs, San Francisco Giants, and New York Mets.

He is a member of one of the sport's most notable families of the late 20th century, being the son of famed first baseman and manager Felipe Alou.

A mainly offensive player who admitted himself that he was not particularly strong on defense, Alou was never a serious Hall of Fame contender, but his career was noteworthy in several respects nevertheless.

[2] Prior to the 1997 season, Alou signed as a free agent with the Florida Marlins, where he led the team with 23 home runs and 115 RBIs.

The Marlins made the playoffs as a wild card team and defeated the San Francisco Giants in the National League Divisional Series.

On November 20, 2006, the New York Mets signed Alou to a one-year contract worth $7.5 million with a club option for 2008.

After hitting .318 in his first month as the regular left fielder, Alou suffered a torn quadriceps muscle and was forced out until August.

On July 9, Alou suffered a torn right hamstring playing in the outfield for AA Binghamton in Norwich, Connecticut.

Mets general manager Omar Minaya stated in a press conference the following day that Alou would likely need surgery and miss the remainder of the 2008 season, which ended his career.

[10] He is the youngest of three sons born to Felipe and his first wife Maria Beltre, who raised him in the Dominican Republic after his parents divorced when he was two.

[11][12] His father Felipe, who managed Moises with the Expos from 1992 to 1996 and the Giants from 2005 to 2006, as well as uncles Matty and Jesús, and cousin Mel Rojas, all had long careers in Major League Baseball.