[1] He began his professional career in the minor leagues in 1991, and spent the next five full seasons there.

Crespo reached the majors in 1996 with the Blue Jays, playing for them until 1998 before joining the San Francisco Giants (2000-2001), and Philadelphia Phillies (2001).

On June 7, 2001, Crespo hit two home runs for the Giants, while his brother César hit his first major league homer with the San Diego Padres, joining a select club that includes Aaron and Bret Boone, Héctor and José Cruz, Al and Tony Cuccinello, Dom and Joe DiMaggio, Graig and Jim Nettles, Rick and Wes Ferrell, and Kyle and Corey Seager.

The seven sets of brothers hit their homers playing for opposing teams.

Following Crespo's MLB career, he played in Japan for the 2002 Yomiuri Giants of the Central League.