born Oct. 1, 1963, Pomona, Calif., U.S.
U.S. baseball player.
McGwire played first base in college, then joined the Oakland Athletics in 1987 and quickly displayed the strength that would become his trademark. His 49 home runs hit during his first season in the majors set a record, and he was named the American League's Rookie of the Year. In 1989 his .343 postseason batting average guided Oakland to the World Series championship. Injuries plagued him in 199395. Traded to the St. Louis Cardinals in 1997, he hit 58 homers. In 1998 he topped Roger Maris 's 37-year-old season record of 61 home runs. He and Sammy Sosa thrilled fans with their home-run competition, and McGwire achieved the new record with 70; the record was broken in 2001 by Barry Bonds (73). In 1999 McGwire hit 65 home runs. Following the 2001 season he retired from professional play.