Hackett's contract as a Westpac Banking Corporation ambassador was not renewed in February 2012 after 13 years in the role, but he remains an employee of the organisation.

[citation needed] Hackett first achieved prominence on debut at the 1997 Pan Pacific Championships, where he first won the 1500 metres.

That record was subsequently broken by Ian Thorpe in the same year at the 1999 Pan Pacific Championships in Sydney, although Hackett himself bettered his old mark.

Entering the Sydney Olympics in 2000, Hackett was the overwhelming favourite in the 1500 m freestyle, and was also expected to help Thorpe take a quinella in the 200 m and 400 m events.

He followed this with an extremely slow swim in the heats of the 4 × 200 m freestyle relay, and was dropped from the final quartet, being replaced by Todd Pearson.

By the time the final of the 1500 m freestyle came, Hackett had qualified third behind sentimental favourite Kieren Perkins, who was being vocally cheered by the crowd.

In the face of the immense pressure, Hackett adopted a more attacking, fast-starting approach, and managed to hang on to claim gold.

He set personal bests in the 200 m, 400 m 800 m and 1500 m freestyle events, finishing second to Thorpe in both 400 m and 800m, and bettering the 800 m world record in the latter.

At 196 cm (six foot five) and 89.8 kg (198 pounds), Hackett won the gruelling 1500 metres race by sheer physical strength and stamina.

He showed this in Sydney when he won despite having only partly recovered from illness, and again in Athens, when he survived challenges from swimmers (Larsen Jensen and David Davies) both six years his junior to hang on to win the race, despite a partially collapsed lung.

In November 2005, Hackett announced his withdrawal from the 2006 Commonwealth Games due to being unavailable for the selection trials because of a minor surgery to correct a shoulder injury.

However, he was given dispensation to act as a non-competing captain in order to mentor the fellow swimmers in the lead-up to the competition.

In December 2007, Hackett competed in and won his first national championship 10 km Open Water race.

By barely edging out veteran open-water swimmer and surf Ironman Ky Hurst, the pair both qualified for the World Championships in Seville, Spain.

However, Hackett failed to finish in the top 10 in this event, and therefore missed out on qualifying for the 10 km open water swim at the 2008 Summer Olympics.

[4] At the 2008 Victorian Short Course Swimming Championships, his final Australian meet before departing for the Olympics, Hackett broke his own 800 metres freestyle world record – lowering the mark by almost two seconds to 7:23.42.

In October 2008, Hackett joined Nine News Melbourne as the weekend sport presenter, replacing Heath O'Loughlin.

[12] On 29 October 2011, police were called to attend a dispute at Hackett and Alley's Melbourne apartment, which was reportedly found in disarray.

He emerged aggressive and agitated, taking offence to a male business class passenger who reclined his seat".

[20][21][22] In 2004 he was granted the "Key to the City of Gold Coast" in recognition of his outstanding achievement as a swimming champion.