Who is the only MLB player to have his uniform number retired by every team?

Jackie Robinson is the only MLB player whose uniform number, 42, has been retired by every team. Major League Baseball retired the number throughout the sport on April 15, 1997, the 50th anniversary of Robinson breaking the modern color barrier.

Robinson debuted for the Brooklyn Dodgers on April 15, 1947, becoming the first Black player in the modern major leagues. His achievement transformed baseball and made him a central figure in the American civil-rights story, despite the abuse, threats, and institutional opposition he faced during his career.

The league-wide retirement was unusual because uniform numbers are normally retired individually by clubs. Robinson's former team, the Dodgers, had already retired No. 42 in 1972. Players who were already wearing No. 42 elsewhere in MLB received grandfathered exceptions, most notably Yankees closer Mariano Rivera, the last active major-league player to wear it.

Since 2009, every player, coach, and umpire has worn No. 42 on Jackie Robinson Day. That annual tribute is different from ordinary team retirement ceremonies: it honors Robinson across MLB rather than associating the number with just one franchise.