[1] He played in Major League Baseball as a catcher for 21 seasons with the Chicago Cubs, St. Louis Cardinals and the New York Giants.

[5] He served as backup catcher working behind Bill Killefer as the Cubs went on to claim the 1918 National League pennant before losing to the Boston Red Sox in the 1918 World Series.

[7] In 1920 O'Farrell caught the majority of the Cubs' games and posting a .248 batting average as, Killefer was injured during the season.

[1] In July 1924, O'Farrell suffered a fractured skull when a foul ball broke his catcher's mask.

[12] He missed most of the season, and lost his job when future Baseball Hall of Fame member, Gabby Hartnett, played well in his absence.

[19] In December 1926, the Cardinals traded their manager Rogers Hornsby to the New York Giants for Frankie Frisch and Jimmy Ring while O'Farrell was named player-manager.

[25] O'Farrell played as a part-time catcher for the Giants, sharing catching duties with Shanty Hogan during John McGraw's final four years as manager of the club.

[1] In October 1932, O'Farrell was traded back to the St. Louis Cardinals for catcher Gus Mancuso as part of new Giants manager Bill Terry's rebuilding campaign.

[27] He spent one season serving as backup catcher to Jimmie Wilson before being traded to the Cincinnati Reds in January 1934.

[29] It was later reported that after the Reds had lost nine consecutive games, O'Farrell was engaged in a conversation with MacPhail when he quipped, "Well, you can't win 'em all."