William James Hollahan
- Bats Right, Throws Right
- Height 5' 8", Weight 165 lb.
- Debut September 27, 1920
- Final Game October 3, 1920
- Born November 22, 1896 in New York, NY USA
- Died November 27, 1965 in New York, NY USA
Bill "Happy" Hollahan was born and died in New York, NY, and started his pro career in the state of New York with the 1920 Rochester Hustlers, hitting .265 and slugging .347. It was enough that the Washington Senators, under manager Clark Griffith, gave Bill a trial near the end of the 1920 season. Bill was in three games, getting a hit and a walk against the Boston Red Sox in his first game on September 27th, and then getting no hits or walks in three more plate appearances in the two other games against the Philadelphia Athletics. He did drive in a run in the last game, however. Bill did not make an error during eleven innings total in the field at third base.
Hollahan was nine years younger than his Senators teammate Walter Johnson.