Mahon was born in
Oxford into an Irish family of musicians. His father William Mahon is thought to have gone to Oxford from Salisbury in the 1740s and to have been an orchestral player in the
Holywell Music Room. His siblings were James Mahon, William Mahon, and Sarah Mahon, who were likewise musicians. Mahon performed his clarinet debut at the
Holywell Music Room, Oxford, in 1772 with a clarinet concerto. Mahon was a member of the
Oxford Volunteers Band. In 1773 he played in London and by 1777 he moved in with his brother William Mahon to live there. In London, John appeared at
Covent Garden,
Hanover Square, the
Haymarket, the
Pantheon, and the Ranelagh. John made several lengthy visits to his hometown of
Dublin during his life. In 1783 he became a member of the
Royal Society of Musicians and played at the annual benefit concerts at
St. Paul's Cathedral in May 1794, 1795, and 1797. Mahon married
Margaret Perry in
Dublin (30 June 1792). John Mahon had many financial troubles in 1814. The
Royal Society of Musicians illustrated his difficulties stating he was "infirm" and requested relief, in which he was granted £40. On 6 October 1816, Mahon sent word that he had received a serious wound in his left hand, which would take two to three months to cure and was granted an additional £30. Mahon eventually retired to
Dublin in 1825. Mahon died in
Dublin, in January 1834, due to ill health. Mrs. Mahon was granted £1 per month survivor's assistance plus £8 for her own eventual funeral expenses. ==Compositions==