He then went on to Christian Brothers' High School, Lewisham and represented them in the New South Wales Combined Catholic Colleges Australian Schoolboys team 1993.

He played in the NRL for the Manly-Warringah Sea Eagles, the Canterbury-Bankstown Bulldogs, the Balmain Tigers, the St George Illawarra Dragons, and in the Super League for the London Broncos/Harlequins RL.

[citation needed] Haumono made his first grade debut for Manly-Warringah in round 11 1994 against Balmain, coming off the bench in a 42–0 victory at Leichhardt Oval.

In 1995, Haumono featured heavily in the Manly side which won the minor premiership having lost only 2 matches all year.

In 1996, Haumono played 14 games but missed out on selection in Manly's premiership winning side which defeated St. George in the grand final.

During the 1998 NRL season, Haumono walked out on Canterbury midway through the year after devising a plan to get out of his contract with the club.

[5] In December 2006, with a year remaining on his contract, Haumono quit rugby league to return to professional boxing.

[citation needed] Haumono briefly held the title of New South Wales heavyweight champion before rejecting an offer to join the stable of American promoter Don King and returning to rugby league.

[9] Haumono is married to Margaret, who is a cousin of his friend and fellow rugby league player-turned boxer Anthony Mundine.