professional baseball player who, with Mark McGwire (McGwire, Mark), entertained fans with a series of home-run races in the late 1990s that rewrote the record books. In 1999 Sosa became the first player to hit 60 homers in two seasons.

As a child, Sosa worked at a number of jobs, including shining shoes, to help support his family following his father's death. At age 14, using a mitt made from a milk carton, he began playing organized baseball, and in 1985 he signed with the Texas Rangers. In 1989 he made his professional debut but was soon traded to the Chicago White Sox. After struggling at the plate, Sosa was sent across town to the Chicago Cubs in 1992. The following year the right fielder became the team's first player to hit 30 home runs and steal 30 bases in one season, an achievement he repeated in 1994. In 1995 he made his All-Star Game debut, and during the 1997 season he recorded his 1,000th career hit. Though Sosa was a powerful hitter, he was also undisciplined—his strikeouts (174) outnumbered his hits (161) that year.

The 1998 season, however, marked a turnaround for Sosa as he became more patient at the plate. After a slow start, he hit 20 home runs in June to set a major-league record for most homers in a single month. Though not expected to threaten Roger Maris (Maris, Roger)'s single-season home-run record (61), he was soon battling McGwire for a place in the record books. On September 13, five days after McGwire had passed Maris, Sosa hit his 61st and 62nd homers. He finished the year with a .308 batting average and 66 home runs, earning him the National League's Most Valuable Player award. On September 18, 1999, Sosa became the first player to hit 60 homers twice; he finished the year with 63. Before the start of the 2005 season, Sosa was traded to the Baltimore Orioles. In March 2005, amid growing allegations of steroid use in baseball, he testified at a congressional hearing that he had never used performance-enhancing drugs. After a lacklustre year with the Orioles, Sosa sat out the 2006 season, but he returned to professional play in 2007 as a member of the Texas Rangers. On June 20, 2007, Sosa hit the 600th home run of his career; he was just the fifth major leaguer to accomplish that feat.