[1] He played his junior football for Logan Brothers in Queensland, Australia before being signed by the Canberra Raiders.

[6] Sa'u then signed a four-year contract starting in 2008 to be a part of the newly cleaned out Newcastle Knights.

[8] In June 2013, it was announced that Sa'u had signed a two-year deal with Salford in the Super League starting in 2014.

On 14 May 2019, after five years with the Salford club, Sau joined fellow Super League team Wakefield Trinity on an initial one month loan.

In round 18 of the 2021 Super League season, he scored two tries for Leigh in a 28-34 loss against Hull Kingston Rovers.

He was also called in the 2013 Rugby League World Cup squad to replace the initially selected Roy Asotasi.