Gillingham, Kent born outside right Jack Mahon began his football career with junior club New Brompton Excelsior in 1929 before joining Doncaster Rovers and spending 1930-31 on their books, without making a senior appearance. He joined Second Division Leeds United in 1931 making his Football League debut at Plymouth Argyle in January 1932, one of only 2 first team appearances he made in what was a promotion season for Leeds. Mahon could play on either wing, but his career took off only after leaving Leeds for West Bromwich Albion in September 1935, having scored 23 goals in 84 appearances for the Elland Road club. At the Hawthorns he was the club’s second top goalscorer in 1935-36 albeit with 17 goals a long way behind the legendary “W.G.” Richardson’s 40. He scored 14 and 13 the following two seasons but couldn’t prevent their relegation in 1938, and returned to Yorkshire to join Huddersfield Town in September 1938 after 44 goals in 123 appearances for The Baggies. Breaking a leg on his Huddersfield debut, he was restricted to a single goal in 7 appearances before the Second World War intervened, although he was fit enough to be selected for the FA Tour to South Africa in 1939 he played in a 2-1 win over the South Africans in the third International “Test Match” clash on 1st July 1939 at the Wanderers Ground, Johannesburg, which the Touring team won 2-1.
During the war he guested with Leeds United, scoring ten times in thirty-three appearances, he also played for several other clubs during the war. In 1939-40 he made two appearances for Bradford City, two for Halifax Town, and one for Torquay United, and scored once for each team. Other clubs included Chelsea, Millwall, Queens Park Rangers, Reading and West Ham United.
He joined York City in the 1945-46 season and played eleven games scoring twice and after peace was declared he scored once in three F.A. Cup appearances, but did not play any League games. After that he went on to coach in Denmark, with IFK Elsborg from 1947 to 1950, Sweden, with IFK Gothenberg from 1950 to 1954, and Malaya before rejoining Leeds as a coach. He ran a youth club in the Dewsbury Road area at that time. He was also coach to York City and joined Hull City as trainer in 1953-54 before retiring
His father, James, had a long association with Gillingham and represented the Southern League against the Football League in 1910. His father and uncle also played for Doncaster Rovers.