Mark McGwire

Did You Know?

• McGwire was drafted in the 8th round by the Montreal Expos in the 1981 amateur draft but did not sign.
• He played college baseball at the University of Southern California, where he was a teammate of Randy Johnson, Jack Del Rio, and Rodney Peete under coach Rod Dedeaux.

Professional career

Mark McGwire was selected by the Oakland Athletics with the tenth pick of the 1984 MLB draft, following three years at the University of Southern California and a spot on the 1984 U.S. Olympic team. He spent the 1984 and 1985 seasons with the Single-A Modesto A’s, then opened 1986 in the minors with the Double-A Huntsville Stars and Triple-A Tacoma Tigers. McGwire made his major league debut on August 22, 1986, and recorded his first hit two days later, in his third game. Over 18 games that season, he hit three home runs and drove in nine runs, but his batting average was just .189.

Still a rookie in 1987, McGwire hit four homers in April, then exploded for 15 in May and nine more in June. By the All-Star break, he had 33 home runs and made the American League All-Star team. On August 11, he surpassed Al Rosen’s AL rookie record of 37 homers, and three days later broke the major league rookie mark of 38, previously shared by Frank Robinson and Wally Berger. In September, he added nine homers while posting monthly personal bests of a .351 average, .419 on-base percentage, and 11 doubles. With 49 home runs and two games left in the regular season, McGwire missed those games to be present for the birth of his first child. He finished 1987 with 118 RBIs, a .289 average, 97 runs scored, 28 doubles, a .618 slugging percentage, and a .370 OBP. His 49 homers stood as the major league rookie record until Aaron Judge hit 52 for the New York Yankees in 2017.

McGwire led the American League in home runs in 1987 and tied for the major league lead with Chicago Cubs right fielder Andre Dawson. He also led the majors in slugging, ranked second in the AL in adjusted OPS (164) and total bases (344), and placed third in RBIs and OPS (.987). He was unanimously voted the AL Rookie of the Year and finished sixth in AL MVP voting. From 1988 through 1990, he hit 32, 33, and 39 home runs, becoming the first major leaguer to hit 30 or more homers in each of his first four full seasons. On July 3 and 4, 1988, he hit game-winning home runs in the 16th inning of consecutive games. As of May 2009, McGwire was tied with Joe DiMaggio for third all-time in home runs over a player’s first two calendar years in the majors (71), trailing only Chuck Klein (83) and Ryan Braun (79).

Honors, records and achievements

Mark McGwire finished his playing days with 583 home runs, placing him fifth on the all-time list when he stepped away. He reached the 500-home-run milestone in 1999 after just 5,487 at-bats, the fastest any player had ever done it. He topped the majors in home runs five times: in 1987 and then every year from 1996 through 1999. His four-year stretch from 1996 to 1999 produced 245 home runs, the most ever in a four-season span.

He was the first player to hit more than 50 home runs in four straight seasons, and the first to hit 49 or more in five different seasons—including a rookie-record 49 in 1987. His career rate of one home run every 10.61 at-bats remains the best in MLB history, ahead of Babe Ruth’s 11.76. As of 2025, McGwire held three of the four lowest single-season at-bats-per-home-run ratios ever, from 1996, 1998, and 1999; those were the top three such seasons until Barry Bonds broke the single-season home-run record in 2001.

His 1997 season ranked 14th on that list, not counting Negro League stats. Known as one of the game’s slowest runners, McGwire hit only six triples, the second-fewest among players with at least 7,000 plate appearances. He stole 12 bases and was caught eight times. His 1,626 career hits are the fewest of any player in the 500-home-run club.

He was named The Sporting News Sportsman of the Year in 1997 and again in 1998, sharing the latter honor with Sammy Sosa. He also shared the 1998 Sports Illustrated Sportsman of the Year award with Sosa and was named the Associated Press Athlete of the Year that same year. In 1999, The Sporting News ranked him 91st on its list of the 100 greatest baseball players, a list compiled during the 1998 season using stats through 1997. That year he was also elected to the Major League Baseball All-Century Team.

An updated list in 2005 placed him at 84th. A five-mile stretch of Interstate 70 near Busch Stadium in Missouri was named Mark McGwire Highway to honor his 70-home-run season and his community work, but in May 2010, St. Louis politicians passed a state bill to rename it Mark Twain Highway.

Steroid use

Mark McGwire's connection to performance-enhancing drugs first became public in 1998, when an Associated Press report revealed he used androstenedione. That substance, an over-the-counter muscle enhancer, was already banned by the NFL and the International Olympic Committee, but Major League Baseball did not prohibit it at the time, and the U.S. government did not classify it as an anabolic steroid until 2004. In 2005, Jose Canseco's book "Juiced" claimed McGwire had used performance-enhancing drugs since the 1980s and that Canseco had personally injected him.

That same year, both players were among 11 people subpoenaed to testify before Congress about steroids. During his March 17, 2005 appearance before the House Government Reform Committee, McGwire gave a tearful opening statement but declined to answer questions under oath. Nearly five years later, on January 11, 2010, McGwire admitted in an interview with Bob Costas that he had used steroids on and off for a decade. He said he used them in the 1989-1990 offseason, after a 1993 injury, and occasionally throughout the 1990s, including the 1998 season.

He explained he took steroids to recover from injuries and for health reasons, not to improve performance, and that his decision to come forward was prompted by his hiring as hitting coach for the St. Louis Cardinals. Despite this admission, McGwire faced criticism for not acknowledging that steroids helped his record-setting home run totals in the late 1990s. Costas noted he gave McGwire multiple chances to make that admission, but McGwire never did.

Personal life

Mark McGwire comes from a family of athletes. His older brother, Dan, played quarterback in the NFL for the Seattle Seahawks and Miami Dolphins after being a first-round draft pick from San Diego State. Another brother, Jay, is a bodybuilder who published a book in 2010 about the brothers’ shared steroid use. McGwire married Stephanie Slemera, a former pharmaceutical sales rep from the St. Louis area, in Las Vegas on April 20, 2002.

The couple had triplet daughters—Monet Rose, Marlo Rose, and Monroe Rose—on June 1, 2010, joining sons Max and Mason. Mason, a pitcher, was selected by the Chicago Cubs in the eighth round of the 2022 MLB draft. Max, who played college baseball at Oklahoma, San Diego, and Saint Louis, signed a minor league contract with the Athletics on July 31, 2026. The family lives in a gated community in Shady Canyon, Irvine, California.

Together, they founded the Mark McGwire Foundation for Children, which supports groups helping kids who have experienced sexual or physical abuse. McGwire also has a son, Matthew (born 1987), from his first marriage to Kathlene Hughes, which lasted from 1984 to 1990. Before he admitted to using steroids, McGwire kept a low profile, spending much of his free time on the golf course. He later worked as a hitting coach for MLB players like Matt Holliday, Bobby Crosby, Chris Duncan, and Skip Schumaker.

McGwire made a cameo as himself on the TV show Mad About You (season 7, episode 13) and voiced himself in a 1999 episode of The Simpsons titled “Brother’s Little Helper.”