[3] Hamer played as a central defender in non-League football making his Isthmian League debut aged 18 against Clapton in 1970 for the Corinthian-Casuals.
In 1975, he left Carshalton Athletic and signed as a full-time professional for Berea Park based in Pretoria and playing in the National Football League.
In the early part of 1976 for personal reasons he returned to the UK and signed for Bromley At the start of the 1976–77 season he became player/manager of the Corinthian-Casuals alongside Paul Sussams.
In 1981, Hamer joined London Weekend Television's Big Match programme working alongside Brian Moore for over 10 years, continuing to do so, even after acquiring the National Sporting Club from Lord Forte in 1987 which was based in the Cafe Royal, Piccadilly, London W1 with former Corinthian-Casuals goalkeeping teammate, past England cricket Captain Bob Willis.
He became chairman of Swansea City in 1997, but was sacked in September 2000 after losing the support of the management team at the Club because of his erratic behaviour.