Oakland Athletics (1997–2015)
Beane succeeded Alderson as general manager on October 17, 1997. He continued Alderson's crafting of the Athletics into one of the most cost-effective teams in baseball. For example, in the 2006 MLB season, the Athletics ranked 24th of 30 major league teams in player salaries but had the 5th-best regular-season record.
The Athletics reached the playoffs in four consecutive years from 2000 through 2003, losing in the American League Division Series each year. In 2002, the Athletics became the first team in the 100+ years of American League (AL) baseball to win 20 consecutive games. After the 2002 season, the Boston Red Sox made Beane an offer of $12.5 million to become their general manager, but he declined. On April 15, 2005, Beane received a contract extension to remain with the Athletics as the team's general manager through 2012, and new team owner Lewis Wolff awarded Beane a small portion of the team's ownership. They won their first playoff series under Beane in 2006 when they swept the Minnesota Twins in the American League Division Series, but were swept by the Detroit Tigers in the American League Championship Series.
From their 2006 playoff appearance until 2012, the Athletics did not make the playoffs or finish above .500, which triggered criticism of Beane and his approach in some quarters, especially in 2009. Beane largely dismisses criticism of his approach, indicating that his philosophy revolves around research and analysis. Many other general managers have followed Beane's strategy and now use similar approaches. In December 2009, Sports Illustrated named Beane #10 on its list of the Top 10 GMs/Executives of the Decade in all sports.
While "Moneyball" had already changed how MLB players were valued, Beane had begun concentrating on high school players, a group he once largely ignored, in the MLB draft, considering them to be heavily undervalued. He and other like-minded GMs also changed their draft strategies to focus more on defensive skills, which became undervalued in the years immediately after the Moneyball revolution. This new emphasis on defense was displayed in the 2010 season; although the Athletics finished at .500 and again missed the playoffs, they led MLB in defensive efficiency, measured as the percentage of balls put into play by opponents that resulted in outs, and allowed the fewest runs in the AL. In February 2012, the Athletics extended Beane's contract through 2019. In the 2012 season, the Athletics again made the playoffs under Beane, winning the AL West title on the last day of the regular season. The Athletics returned to the playoffs in 2013 by winning the American League West division title again, the team's first back-to-back division championships since the 2002 and 2003 seasons.
On October 5, 2015, the Athletics announced that Beane had been promoted to executive vice president of baseball operations. Assistant GM David Forst assumed the job of general manager. In November 2022, Beane became senior advisor to owner John Fisher, and Forst became the new head of baseball operations. Under Beane's tenure as general manager, the Athletics reached the postseason eight times (2000, 2001, 2002, 2003, 2006, 2012, 2013, 2014) but won just one postseason series (the ALDS in 2006), which included seven consecutive losses (five of them in Oakland) in a winner-take-all game.
