After playing for minor teams Clowne White Star and Worksop Town he joined Football League club Gainsborough Trinity in 1908.

He remained with the club, later renamed Gillingham, until 1920 and made over 250 appearances.

[3] In 1920, he left Gillingham to join Doncaster Rovers[1] where he played in their first game in their return to football following WW1, in the 2–1 defeat to Rotherham Town in the Midland League.

[4] His son, also called Jack Mahon, played professionally, notably for Leeds United and West Bromwich Albion in the 1930s.

This biographical article related to association football in England, about a midfielder born in the 1880s, is a stub.