Allan H. "Bud" Selig's tenure in Major League Baseball (MLB) is marked by a series of transformative changes and challenges. Born on July 30, 1934, in Milwaukee, Wisconsin, Selig's journey in baseball administration began long before he assumed the role of Commissioner. He initially gained recognition as the owner and team president of the Milwaukee Brewers, a position he held from 1970 until he became acting Commissioner of Baseball in 1992.

Selig's leadership as Commissioner officially began in 1998, following a six-year period as the acting head of MLB. His era was characterized by a focus on modernizing the game and addressing various issues that had long plagued the sport. One of his early and most controversial actions was overseeing the realignment of teams and the introduction of the Wild Card system in 1994, which expanded the playoff format and increased fan engagement by allowing more teams to compete in the postseason.

The late 1990s and early 2000s were a period of both growth and turmoil for MLB under Selig's watch. The league experienced a surge in popularity, partly due to the thrilling home run race between Mark McGwire and Sammy Sosa in 1998. However, this era was later overshadowed by revelations of widespread performance-enhancing drug use among players. Selig faced criticism for the league's initial slow response to the steroid crisis, but he eventually implemented stricter drug testing policies and penalties, which helped restore some integrity to the sport.

Selig also played a role in the economic restructuring of MLB. He introduced revenue-sharing models aimed at reducing financial disparities between large-market and small-market teams. This initiative sought to create a more level playing field and ensure the long-term viability of all franchises. Additionally, Selig was instrumental in negotiating labor agreements that helped avoid work stoppages, a significant achievement given the history of labor disputes in baseball.

Interleague play, another of Selig's initiatives, began in 1997 and allowed teams from the American League and National League to compete against each other during the regular season. This move was initially met with skepticism but eventually became a popular aspect of the MLB schedule, offering fans new and exciting matchups.

The introduction of instant replay in 2008 marked another milestone in Selig's tenure. Initially limited to reviewing home run calls, the use of replay expanded in 2014 to include additional aspects of the game, aiming to improve the accuracy of umpire decisions and enhance the overall fairness of the sport.

Selig's time as Commissioner was not without controversy. The 2002 All-Star Game ended in a tie after both teams ran out of available pitchers, leading to widespread criticism and prompting changes to the game's format. In response, Selig announced that the league that won the All-Star Game would receive home-field advantage in the World Series, a rule that remained in place until 2016.

Under Selig's leadership, MLB also saw the relocation and expansion of teams. The Montreal Expos moved to Washington, D.C., in 2005, becoming the Washington Nationals. This move was part of a broader effort to stabilize struggling franchises and expand the league's reach into new markets.

Selig retired as Commissioner in January 2015, succeeded by Rob Manfred.