Fifita played his junior rugby league for Souths Acacia Ridge. In 2015, he was 18th man for the Queensland Under-16 rugby league team, despite being a year younger. He then competed at the ASSRL U15s Tournament, playing for Queensland U15s Schoolboys Maroons team. He was selected for the Australian U15s Schoolboys Merit team. In 2016, he was once again selected for the Queensland Under-16 rugby league team at and captained the side. He was part of the Keebra Park side, which also featured Payne Haas, that narrowly lost to Westfields Sports High School in the GIO Schoolboy Cup Final. In 2017, Fifita competed at the ASSRL U18s Tournament, playing for Queensland U18s Schoolboys team. He was chosen for the Australian U18s Schoolboys team, which toured New Zealand. Later in the year, he captained Keebra Park in the GIO Schoolboy Cup Final against Westfields Sports High School, which Keebra Park won.
2018
On 13 February 2018, extended his contract with the Broncos to the end of the 2020 season. Fifita started by the year by playing in the Queensland Cup for the Souths Logan Magpies. In Round 16 of the 2018 NRL season, Fifita made his NRL debut for the Brisbane Broncos against the Canberra Raiders, becoming the first player born in the 2000s to make his NRL debut. Fifita played 47 minutes off the interchange bench during the 26-22 comeback win at Suncorp Stadium and coach Wayne Bennett commented on his impressive debut, "I liked it because he played mistake free and that is all you can ask", "He was good and never let anybody down, He did a really good job for us." In Round 23 against the South Sydney Rabbitohs, Fifita scored his first NRL career try in the Broncos 38–18 win at Suncorp Stadium. Fifita finished his promising NRL debut year with him playing in 11 matches and scoring 2 tries for the Broncos in the 2018 NRL season. On 17 December 2018, Fifita was selected in the 15-man emerging Queensland squad.
2019
On 15 February 2019, Fifita represented the Indigenous All Stars against the New Zealand Māori All Stars team, playing off the interchange bench and scoring a try in the 34–14 win at AAMI Park. After having some solid performances leading up to the 2019 State of Origin series, Fifita earned selection in the Queensland Maroons squad. Fifita will make history as he is the first player born in the 2000s to play Origin, Queensland Coach Kevin Walters commenting about his selection, "I rang him and told him he had made the Queensland under 18 team," Walters said on Monday. "He said, 'No, I am too old for that, "I said, 'Well you better come and play Origin then.'" On 30 September, Fifita was named on the bench for the Australia PM XIII side. On 7 October 2019, Fifita was named at second row for the U23 Junior Australian side.
2020
On 27 April, it was revealed that Fifita would be ruled out from playing indefinitely after undergoing knee surgery. On July 25, it was announced that Fifita had signed a record three-year deal, worth over $3 million with the Gold Coast.
Controversy
On 9 November 2019, Fifita was arrested in Bali after an alleged altercation with a bouncer at a nightclub called La Favela. On 11 November Fifita was released from jail after the bouncer who was allegedly assaulted accepted Fifita's apology. After Fifita left the prison he spoke to the media saying "I want to thank everyone involved and obviously, the police. I will make a further statement later in the week". On 13 November 2019, it was revealed by Fairfax Media that Fifita secured his freedom from the Bali jail after paying $30,000 and signing a "peace agreement". They also revealed that Fifita spent five hours in isolation immediately after his arrest. He was then presented with a local legal representative and signed over power of attorney before a Brisbane welfare officer arrived to help negotiate the peace agreement. He was also forced to urinate in a water bottle in his cell. Brisbane Broncos CEO Paul White spoke to the media saying "I don’t know too many 19-year-old men... of his background, who have had an experience like that, I know, having a policing background, that being in a cell is not a great experience, and being in one in a foreign country was pretty confronting. He’ll learn a big lesson".
