As a player-manager, he led the Senators to two seventh-place finishes, and in his second managerial stint led the Red Sox to the 1912 World Series title. His success was short-lived, as he had a falling-out with his teammates and resigned midway through the 1913 season. His successor, Bill Carrigan, would win two more World Series titles for the Sox. Stahl died of tuberculosis in Monrovia, California at age 43.
Stahl has a measure of immortality as the acknowledged eponym of the term "jaking it", a baseball phrase for faking an injury to stay out of the lineup, or otherwise loafing.
Stahl was not related to Red Sox teammate Chick Stahl, despite contemporary accounts erroneously listing them as brothers.