Walter John Mueller (December 6, 1894 – August 16, 1971) was a professional baseball player who played outfield in the Major Leagues for the Pittsburgh Pirates, from 1922 to 1926.

[2] He began the 1922 season with the Pirates, but he sat on the bench for three weeks before the team's manager, George Gibson, gave him a chance to play.

[4] The pitch that resulted in the historic home run, was thrown by future Hall of Famer, Grover Cleveland Alexander.

The game's boxscore credited the home run to Claude Rohwer, who was on the Pirates roster to start the 1922 season, but was set to the minor leagues several days later.

[5] He remained the only Pirate to homer on the first pitch of his first major league start until Starling Marté accomplished the feat on July 26, 2012.