[6] In June 1989, at age 12, Hann became the youngest qualifier for the Australian men's open snooker championship, only losing in the last 16 stage to the Under-21 national champion Steve Mifsud.

Although he broke his left wrist in a motorcycle accident which caused him to play in a plaster cast, he won the Victoria Under-12 Championship in March 1990.

[5] At the age of 13, Hann compiled his first century break (a 103) in a match against Melbourne Senior Champion Garry Cullen.

[9] On 13 October 1991, Hann was given a suspended ban by the Australian Billiards and Snooker Council from all domestic and overseas competitions for spitting on a competitor's mother.

This was invoked after the New South Wales country junior championship in January 1993 when he swore at the referee following a decision that favoured his opponent and entered the Lithgow Workmen's Club licensed poker-machine area.

[18] One month earlier, Hann became the first Australian player since Eddie Charlton in 1992 to qualify for the World Snooker Championship.

After the tournament, he met with his mother and World Snooker chairman Rex Williams, and agreed to change his lifestyle and public image.

[20] Hann advanced to the quarter-finals of the Grand Prix tournament in the following month,[21] losing to Stephen Lee in a 5–0 whitewash.

[22] He lost 5–9 to Marcus Campbell in the second round of the UK Championship in November; Hann's opponent criticised him for conceding two frames in the match.

[23] Hann replicated this performance once more during the season, this time in the Scottish Open in February 1999, losing 2–5 to Graeme Dott.

[19] Before the start of the 1999–2000 snooker season, Hann won the WEPF World Eightball Championship to become the only player born outside the United Kingdom and Ireland to claim the title,[25] and defeated Oliver Ortmann to successfully defend the Lindrum Masters tournament in August.

[29] While doing this, he sustained a clavicle fracture and a bruised wrist in an accident in Melbourne,[28][30] which left him unable to play in the next six tournaments.

[31] Hann returned to competition at the Scottish Open in March 2000, reaching the second-round where he lost 4–5 to eventual champion Ronnie O'Sullivan.

[33] Hann was eliminated from the second round at the Grand Prix tournament,[34] and was booed by spectators for smashing the cue ball into the pack of reds in the final three frames of his match against O'Sullivan.

[36] Hann broke a bone in his foot in a parachute jump before the 2000 UK Championship,[37] and was required to play shoeless in a tournament,[38] in which he lasted until the quarter-finals.

[33] Players and pundits criticised Hann for breaking up the red balls in a pool-style method during both of his matches and for unprofessional-ism in the second game.

[2] Hann's top sixteen world ranking allowed him to enter the non-ranking Masters tournament for the first time in his professional career,[48] which he lost in the first round 4–6 to Lee.

[60] After the match, referee Lawrie Annandale separated the two players from a physical alteration after Hann made a threatening comment to Hicks when the latter suggested he would lose his top 16 world ranking.

[68] A hearing at the World Professional Billiards and Snooker Association (WPBSA) was convened after its panel was shown transcripts of video and audio footage of the meetings which took place between Hann and the undercover Sun journalists in March and April 2005.

"[74] In October 2001, Hann invited an unidentified South African born woman to a hotel in London after midnight.

[75] He was instructed to surrender his travel documents and a Magistrates' Court judge allowed him to keep playing professional snooker as long as he told the police where he was residing.

One of them claimed that he repeatedly struck her, an accusation that Hann strongly denied explaining that his mother had taught him to never raise a hand to a woman.

[79] Ultimately the case turned on the credibility of his accuser, which was undermined when it was admitted she had lied consistently under oath throughout the trial.

ASIC temporarily banned Monarch FX and Hann from offering financial services until November 2014 when the hearing resumed.