Across seven-and-a-half years with South Sydney, the late-blooming five-eighth has developed a reputation as a fiery customer.
Rabbitohs teammates have repeatedly pointed to Walker's passion for the game as grounds for his temperament, of which Souths' rivals have begun to take advantage.
Walker notably refused to shake Cameron McInnes' hand following a tight loss to Cronulla last year after the Sharks baited him on their way to victory.
Early this season, the 33-year-old pushed Sydney Roosters halfback Sam Walker over in backplay and conceded a penalty that marched Souths' rivals upfield to win the game.
After two years out of NSW calculations, Walker will make his return on July 12, usurping Jarome Luai at five-eighth as NSW hope to avoid a series whitewash.
No arena in rugby league is more emotional than State of Origin but Walker said he'd worked hard on his temper this season and would remain unflappable at Accor Stadium.
"I've been doing it pretty well (this year)," he said.
"I'm not getting angry and things like that. It's probably something that I've worked on over the last couple of years.
"There'd be different times when I'd lose my shit, as people would say.
"This year, I really focused on what I need to do to get out of that headspace or what my team needs of me in that particular time."
Walker's status as a senior player has helped motivate the change. Since the departure of Adam Reynolds at the end of the 2021 season, the inexperienced Lachlan Ilias has played opposite Walker as halfback.
"I understand my role in the team as being one of the senior playmakers in the team that the team depends on, that calm head," he said.
"There's probably two games (this year) I can think of where I probably let my head get the better of me, which is disappointing.
"But I'm not a perfect player. I'm not a perfect person.
"I'm always learning, trying to improve areas of my game. That's understandable to dip in and out of that but it's how I turn around and bounce back from that."
It was Luai who ousted Walker from the Blues side in 2021 and had kept him out thereafter.
Luai's combination with Penrith teammate and Blues halfback Nathan Cleary, currently injured, had made him an enticing prospect for coach Brad Fittler and there were times Walker thought his ship may have sailed after four Origin games.
"There were times when I did think it had sailed," Walker said.
"Last year I don't think I was playing the greatest footy at the start of the year to warrant selection.
"I probably haven't played my greatest footy in the sky blue jersey.
"(Origin III) is a chance for me to right those wrongs."
Now that he's back in the fray, Walker is intent on staying put.
"That's the goal of any player coming into a rep team, they want to be in it for as long as they can," he said.
"I know I've got a wonderful opportunity to go out there and showcase my skills on one of the biggest arenas there is."
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