Lafai was born in Savaii, Samoa, and moved to Auckland, New Zealand as a 6-year old before immigrating to Sydney, New South Wales, Australia as a 9-year old and is of Tuvaluan descent.

[3] Lafai attended Sarah Redfern High School, graduating in 2009 while playing his junior football for the Minto Cobras, and Campbelltown Warriors.

In 2007, Lafai played for the Western Suburbs Magpies Harold Matthews team before being signed by the South Sydney Rabbitohs.

[7] Lafai returned to the Canterbury first grade side in round 5 filling in for the injured Steven Turner, scoring a try in the Bulldogs 46-12 victory over the Parramatta Eels at ANZ Stadium.

[8] In round 13 against the South Sydney Rabbitohs, Lafai suffered a dislocated right shoulder sidelining him for the rest of the year in the Bulldogs 23-18 win at ANZ Stadium.

Lafai returned to the Canterbury-Bankstown first grade side in round 5 filling in the suspended Krisnan Inu in the centres in the Bulldogs 20-6 defeat by the Manly-Warringah Sea Eagles at ANZ Stadium.

[12] On 5 October 2014, in Canterbury-Bankstown's 2014 NRL Grand Final against South Sydney, Lafai played at centre in the club's 30-6 loss.

[15][16] In August, it was rumoured that Lafai was going to sign with the Manly-Warringah Sea Eagles for the 2016 season to make way for Parramatta Eels player Will Hopoate at the Bulldogs, but that was later dismissed.

[23] In round 10 against the Canberra Raiders, Lafai scored his first club try for the St George Illawarra Dragons in the 16-12 golden point extra time win at Jubilee Oval.

[36] In the 2023 Super League season, Lafai played 19 matches for Salford as the club finished 7th on the table and missed the playoffs.