[2] He was a part of the Cronulla team that won their maiden premiership title in the 2016 season, scoring the equalising try that led to the game winning conversion from James Maloney.

On 25 October, Fifita made his international debut for Tonga, starting at prop in the 6–22 loss against Samoa at Parramatta Stadium.

"[13] On 15 July, Fifita signed with the Cronulla-Sutherland Sharks on a 3-year deal, starting from 2012 after was released from the Wests Tigers, along with Bryce Gibbs, so that the club could accommodate Adam Blair under the salary cap.

[15][16] In round 1, Fifita made his debut for the Cronulla-Sutherland Sharks against his former club, the Wests Tigers, playing off the interchange bench in the 16–17 loss at Leichhardt Oval.

[18] With the Sharks starting 2012 well, and with his old club struggling to win early games, Fifita commented, "We have an unbelievable bond.

[23] On 5 June, Fifita made his State of Origin debut for New South Wales against Queensland, where he played off the interchange bench in the Blues 14–6 win at ANZ Stadium.

[26] On 26 October, he made his international debut for Australia against England where he played off the interchange bench in the 28–20 win at Millennium Stadium.

[30] On 11 March, Fifita signed a four-year contract worth more than $800,000 a season to play with the Canterbury Bankstown Bulldogs.

Canterbury's management team were also reportedly upset with Fifita's comments days after signing with the club saying that "He wished he joined Rugby Union instead" and that his "heart was still with Cronulla".

[36] The injury resulted in Fifita missing the 2014 State of Origin series, and a big chunk of the NRL season.

On 17 August, Fifita was involved in a road rage incident at Taren Point where he allegedly threw an object at a car travelling behind him and later after the pair pulled over, Fifita allegedly got out of his Jeep and verbally abused the 23-year-old male driver of the Subaru before punching and kicking the panels of his car.

[44] On 6 August, Fifita and his twin brother David were given 6-week suspensions and a $30,000 fine after they abused a referee at a junior match in Penrith.

[46] During the suspension, on an episode of The Footy Show, Fifita discussed how he had suffered severe depression in October 2014 and attempted suicide by trying to hurl himself out of a 20th story window at a holiday resort at Surfers Paradise after a drunken night out with his brothers and friends celebrating a friend's bucks night.

"[48] Fifita had become suicidal amid the pressures of his team's poor results, a personal form slump and complications involving his contract.

Following the incident, Andrew's brother David forced him to seek psychiatric help after which he received treatment for depression and a personality disorder.

In September 2016, sports journalist Rebecca Wilson called for Fifita to be terminated by Cronulla after the player had visited convicted killer Kieran Loveridge in prison.

[50][51][52] On 2 October, Fifita played for Cronulla-Sutherland against the Melbourne Storm in the 2016 NRL Grand Final, which Cronulla won 14–12 at ANZ Stadium in Sydney.

On 13 December 2016, Fifita was handed a breach notice by The NRL for showing support for childhood friend, one punch killer Kieran Loveridge.

[54][55] On 31 May 2017, Fifita played for the New South Wales Blues in game 1 of the 2017 State of Origin series and was instrumental in the team's 28–4 win over the Queensland Maroons.

During RLWC 2017, despite being named in the Australian team, Fifita opted to play for Tonga, and was instrumental in their most successful World Cup campaign to date, reaching the semi-finals.

On 2 December 2017, it was revealed that Fifita was taking NRL club Canterbury to court over a contract dispute which was reportedly worth $3.2 million over 4 seasons.

According to the report, Cronulla were in talks with securing a major sponsor for the next five seasons equaling $6 million but the deal was cancelled due to Fifita and fellow Cronulla player Josh Dugan's antics during a podcast back in August 2018 when Fifita called Daily Telegraph sports columnist Phil Rothfield a "complete fuckwit" and Dugan calling Rothfield an "old, weathered and baldheaded idiot".

[58][59] In the historic first ever rugby league Test between the Australian Kangaroos and Tonga, Fifita led the Tongan pre-match warcry, the sipi tau, in front of a sold-out crowd at Auckland's Mount Smart Stadium.

[66] In round 22 against Newcastle, Fifita was taken from the field in the first half of the match and later taken to hospital with a suspected throat injury,[67] where he was diagnosed with a fractured larynx requiring surgery and placed into an induced coma.