Sweeney attended St. Ignatius College Prep in Chicago, Illinois, and played for their baseball team as a catcher.

[1][3] Sweeney made his professional baseball debut with the Columbia Gamecocks of the Class C South Atlantic League in 1905.

[12] Ford joined the Highlanders in 1910, and told Sweeney about how he had learned to throw the emery ball following the initial discovery in 1907.

[20] Sweeney again led the league in caught stealings that year, with 133, but also allowed the most stolen bases (205) and passed balls (19).

Claimed by both leagues,[23] Sweeney signed with the Yankees for $9,000 ($273,767 in current dollar terms), the largest salary for a catcher to date.

[24][25] Ford jumped to the Federal League before the 1914 season, and Sweeney taught the emery ball to Ray Keating, a spitball pitcher.

Eddie Collins became suspicious after striking out, and asked Tom Connolly, the home plate umpire, to inspect the ball.

[38][39] Commissioned as a sergeant, he managed U.S. Army baseball teams in 1918,[40] before serving on the front lines in France with the 161st Artillery Brigade.

[41] The Yankees traded Sweeney to the Pittsburgh Pirates of the National League for Gus Getz and Hooks Warner before the 1919 season.

[44] Sweeney signed with the Seattle Rainiers of the Class AA Pacific Coast League for the remainder of the 1919 season.

His father was a battalion chief in the Chicago Fire Department[1] and a contractor who built a garage for his sons, Ed and Gene, that they turned into a taxi business.