In his prime, he was perhaps the closest thing to Babe Ruth that modern baseball has seen. Like Ruth, he was a big man, and a prolific home run hitter; he hit the ball out of the park once in every 9.42 at bats. Like Ruth, he had begun as an outstanding pitcher. And like Ruth, he was a superb low ball hitter who learned to golf the ball for titanic home runs, balls that sometimes cleared the fences with 100 feet to spare.
McGwire ended his career with 583 home runs, which is fifth on the all-time list. He hit 50 or more home runs for four seasons in a row (1996-1999), was a league leader 4 times, and broke the long-standing single season home run record in 1998 when he hit 70 (since broken by Barry Bonds).
McGwire worked hard on his defense, and resisted being seen as a one-dimensional player.
McGwire also had a sense of baseball history that is rare among modern players. He graciously involved the family of Roger Maris in the year that he broke Maris's single season home run record.
McGwire won a silver medal with the USA amateur baseball team in the 1984 Summer Olympics.
Mark McGwire's career totals: