Mann was one of the founding members of St Sidwell’s United, the club that became Exeter City in 1904.

Having previously turned out for St John’s (another Exeter club), he joined the new St Sidwell’s United club that had been formed largely by a group of 16- and 17-year olds who had attended St Sidwell’s school and lived close to the current St James’ Park. 

Playing at centre-half, he is first recorded as a member of the side that faced St David’s on 12 October 1901 although it is entirely possible that he had played in previous games for which records no longer survive.

Scoring his first league goal against St Luke's College Reserves on 2 November 1901, he played regularly during the club’s first two seasons and only missed the occasional game during the third season. 

There is no record of him playing for the first-team once the club became Exeter City in 1904. 

[No candidate from the immediate St Sidwell’s area in the 1901 census but James Mann (17), a tailor of Duke’s Place off Fore Street a possibility. Close to St John's church given his earlier club].