Jack "Kid" Wolfe, was an American professional boxer. He was the first World Champion in the Junior Featherweight division. During his career he had no decision newspaper victories over reigning bantamweight champions Johnny Ertle, Joe Lynch, Kid Williams and Pete Herman, and fought future lightweight champion Sammie Mandell. Wolfe also fought the talented boxers Frankie Jerome, 1918 world bantamweight champion "Memphis" Pal Moore, Young Montreal, Pete Zivic, Dick Loadman, Al Shubert, John "K.O." Eggers, Terry Martin, Danny Frush and Eddie O'Dowd.

Johnny Ertle or Ertel was a Hungarian born American boxer. Nicknamed "Kewpie" and "Little Dynamo", he was a disputed bantamweight world boxing champion from 1915 until 1918, when he lost the title to Memphis Pal Moore. Trained and managed from 1913, when he was only sixteen, by Mike McNulty, Ertle's body punches were particularly devastating to his opponents, because of the extraordinary leverage he could apply using the extra space provided by his small stature. He was managed by Mike Collins in his later career.