Prior to 1969, the American League champion (the "
pennant winner") was determined by the best win–loss record at the end of the regular season. There was one
ad hoc single-game playoff held, in 1948, due to a tie under this formulation. The ALCS started in 1969, when the AL reorganized into two divisions,
East and
West. The winners of each division played each other in a best-of-five series to determine who would advance to the World Series. In 1985, the format changed to best-of-seven. In 1981, a
division series was held due to a split season caused by a
players' strike. In 1994, the league was restructured into three divisions, with the three division winners and a Wild Card team advancing to a best-of-five postseason round, known as the
American League Division Series (ALDS). The winners of that round then advanced to the best-of-seven ALCS; however, due to the
player's strike later that season, no postseason was played and the new format did not formally begin until 1995. The playoffs were expanded in 2012 to include a second Wild Card team and in 2022 to include a third Wild Card team. The ALCS and NLCS, since the expansion to best-of-seven, are always played in a 2–3–2 format: Games 1, 2, 6, and 7 are played in the stadium of the team that has
home field advantage, and Games 3, 4, and 5 are played in the stadium of the team that does not. The series concludes when one team records its fourth win. Since 1998, home field advantage has been given to the team that has the better regular season record, except a division champion would always get home advantage over a
Wild Card team. If both teams have identical records in the regular season, then home field advantage goes to the team that has the winning head-to-head record. From 1969 to 1993, home-field advantage alternated between the two divisions, and from 1995 to 1997 home-field advantage was determined before the season. Nine managers have led a team to the ALCS in three consecutive seasons; the record for most consecutive ALCS appearances by a manager is jointly held by
Joe Torre, who led the
New York Yankees to four in a row (1998, 1999, 2000, 2001), and
Dusty Baker, who led the
Houston Astros to four in a row (2020, 2021, 2022, 2023). The Astros (2017–2023) are also the only team in the American League to have made seven consecutive American League Championship Series appearances.
Tony La Russa and
Jim Leyland are the only managers to lead their teams to three consecutive League Championship Series appearances in both leagues. The
Milwaukee Brewers, an American League team between 1969 and 1997, and the
Houston Astros, a National League team between 1962 and 2012, are the only franchises to play in both the ALCS and NLCS. The Astros are the only team to have won both an NLCS (
2005) and an ALCS (
2017,
2019,
2021, and
2022). Every current American League franchise has appeared in the ALCS. ==Championship Trophy==