Having won the 2000 NRL Premiership, Brisbane travelled to England to play against 2000's Super League V Champions, St Helens R.F.C.

In his final year with the club, Walker (along with Lote Tuqiri and Darren Lockyer), he was the top try-scorer for the Broncos in the 2002 season.

[7] He returned to play on the wing and score a try for the Roosters in their 2004 NRL Grand Final loss to cross-Sydney rivals, Canterbury-Bankstown.

In early March 2007, after a series of strong performances in pre-season trial matches for the Titans, Walker signed a one-year deal with the Gold Coast club for their inaugural season in the NRL.

[12] In 2008, Walker suffered a season-ending ruptured Achilles tendon for the second time in five months,[13] necessitating a lengthy spell on the sidelines.

In 2009, he attracted interest from Super League clubs, but said he did not want to play in Europe and he would prefer to stay in the NRL with a Queensland team.

[14] Unable to secure a desirable contract in the NRL, Walker signed a two-year deal with the Catalans Dragons in France, to commence in 2010.

[16] However, after only six games and a string of injuries, he approached Parramatta officials for permission leave the club and retired from the NRL at the end of the 2011 season.

Under the co-coaching of his brothers Ben and Shane, he played in the 2015 NRL State Championship final where Ipswich defeated Newcastle.