He learnt his trade as a bare-knuckle and booth fighter and established a big reputation. Recognised as the best in Britain, it was planned to send him to New Orleans to face world champion Bob Fitzsimmons – a bout that had the potential to make him Wales’ first world title holder. But O’Brien was struck by sciatica and was kept out of the ring for two years.
On his return he enjoyed one victory before being pitched in against Frank Craig. Craig, known as the ‘Harlem Coffee Cooler’, was recognised in the US as the ‘coloured middleweight champion of the world’, and he proved too much of a challenge for O’Brien, destroying the Welshman in two rounds.
The pair would meet again in unfortunate circumstances six months later. Craig’s planned opponent pulled out at the last minute and an intoxicated O’Brien was thrown in as an emergency replacement. The Cardiffian lasted the first round but then quit, a decision that ended his career on the London fight scene.
Alcoholism and rheumatism blighted O’Brien’s later career and life, and he died of Bright’s Disease at Cardiff Union Infirmary at the age of 43.