Described as a teen prodigy,[5] Sua'ali'i received significant media attention during contract negotiations in 2020[6] as well as during his announcement in March 2023 of switching to rugby union starting in 2025.

In 2021, he was granted an exemption to play in the NRL prior to his 18th birthday, prompting discussions about the welfare of young players.

[7][6] Sua'ali'i was born in Penrith, a western suburb of Sydney, New South Wales, the son of a Samoan father and an Australian mother of Cambodian and European heritage.

[8] He grew up playing rugby league for the Glenmore Park Brumbies and then moved to the Coogee Wombats from age 12.

[14][15] Conflicting reports in mid-2020 suggested that Sua'ali'i had agreed to a multi-million dollar contract with either the Rabbitohs,[16][17][18] or Rugby Australia, which they denied.

[23] The signing was officially announced on 1 December, with Sua'ali'i joining the Roosters effective immediately after he was released from the final year of his Rabbitohs contract.

[26][27] Sua'ali'i made his NRL debut on 22 May 2021, playing at centre for the Sydney Roosters in their round eleven loss to the Brisbane Broncos.

[31] Sua'ali'i scored his first NRL try the following week as the Sydney Roosters defeated the Canberra Raiders in round twelve.

[32][33] Sua'ali'i played in the Roosters' next three fixtures (Gold Coast Titans, Penrith Panthers, Melbourne Storm), winning one and losing two.

Following the Roosters' heavy round sixteen defeat to the Melbourne Storm, Sua'ali'i did not play again for the remainder of the season, as, announced on 13 July 2021, he had accrued a foot injury.

He played 21 matches for the Sydney Roosters in the 2023 NRL season as the club finished 7th on the table and qualified for the finals.

[53] Weeks later, and a month before the 2021 Rugby League World Cup, Sua'ali'i responded to the call-up stating his intentions to play for Samoa.

[53][55] Sua'ali'i played every minute of Samoa's 2021 Rugby League World Cup campaign, in which they started in Pool A against hosts England.

[59][60] It was originally cited a month prior (July 2022) that RA had a number of NRL players in their sights to target before the 2027 Rugby World Cup to be hosted on home soil.

[61][62] Although the reports were confirmed by Rugby Australia Chairman Hamish McLennan, he denied the price-tag associated with Sua'ali'i as being “fanciful”.

You brought a lot of boys and girls through the turnstiles and we wish you the best when you go in two years' time.”[77] As Sua'ali'i was in the Australia squad throughout November 2024, he missed being with the Waratahs in their early off-season.

He was also ruled out ahead of a rivalry clash in early February against the ACT Brumbies with "knee soreness" despite being named as the starting fullback.

[79][80] Despite this ua'ali'i was cleared to play for the Waratahs in their first round home game of the 2025 Super Rugby Pacific season against New Zealand side, the Highlanders.

[89] In the Autumn Nations Series fixture gainst Scotland he looked to have sustained a hand injury in the first half after a big tackle on Sione Tuipulotu forcing an early substitution.

While his side went on to lose 27–13, his first loss in international rugby union, he was later cleared of a broken wrist and eligible to play in their final fixture of the series.