Like his elder brother
Ben and younger brother
Chris, Walker started playing in the
National Rugby League with the
Brisbane Broncos. Having won the
2000 NRL Premiership, the Broncos traveled to England to play against 2000's
Super League V Champions,
St Helens R.F.C. for the
2001 World Club Challenge, with Walker playing from the interchange bench in Brisbane's loss. Walker later moved to the
South Sydney club. In 2019, Walker spoke about his time at South Sydney saying "I went to Souths because Chris was going there. I’d heard how easy it was to get mixed up with the wrong crowd in Sydney. I thought there was a fair chance he could go off the rails… so I went down to help him out. I wasted my time, didn’t I? Ten weeks later he went to the
Sydney Roosters". "I understood the significance of playing at Souths and the history. I recognised that I was lucky to wear the red and green play for Souths. You’d win a game, come up the escalators into the leagues club at Redfern and the place would be packed. The supporters would be in the auditorium and different guys would get up and talk and they’d be whipped into a frenzy. It was wonderful because in that Redfern area there are a lot of battlers. On top of that they fought like hell to get their team back in the comp. There was a lingering memory of that and the thought that perhaps their team might be taken away from them if they didn’t start winning. They were always proud of you – but they wanted a winning team to be happy about". ==Post playing==