Cooper Cronk has announced his retirement at the end of 2019, bringing the curtain down on one of the finest playmaking careers in rugby league history.

Cronk will wrap up his glittering 16-year NRL career at season's end as the most experienced half in NRL history, with 357 Telstra Premiership appearances already to his name on top of 38 Tests for Australia and 22 Origins in Queensland’s most dominant era.

He tallied four grand final wins and another four appearances in more than 300 games with Melbourne, where he joined Cameron Smith and Billy Slater in one of the most decorated trios of the the modern game.

"I've got a lot of people to thank, the Roosters, Storm and family. I'd just like to thank the entire rugby league community," he said with Roosters teammates and coaches watching on at the SCG.

"The game doesn't exist without the NRL community and therefore I wouldn't exist. The game cops its whacks but the game has the ability to transform lives and it has transformed mine.

Cooper Cronk and Billy Slater after the 2018 grand final.
Cooper Cronk and Billy Slater after the 2018 grand final.

"To members, fans, supporters of both the Melbourne Storm and Sydney Roosters - thank you very much. You created an environment, an atmosphere of plenty of support.

"Without Melbourne Storm in my life I'm not the person I am today. I just really appreciate everything Melbourne Storm did for me. I moved down as a teenager and without them I wouldn't be standing here today."

Cronk paid tribute to what he described as "the real big three" of the Melbourne Storm - Slater, Smith and coach Craig Bellamy.

"Those two guys will go down as the best two players in their position. That makes me the best third wheel the game's ever seen because I just jumped off the back of them," he said.

"My job was pretty easy I would get the ball from one future Immortal and pass the ball to another future Immortal, so things were pretty cruisy.

"I'll be forever grateful for what those two guys did for me on and off the field. I'm pleased and humbled my name gets mentioned in the same breath as those two.

"There's not too many people I respect on this planet more than Craig Bellamy. He's never shouted me a beer in 15 years, I can't wait for him to shout me a beer. He's a mate first and coach second.

"The work ethic, the humility, the dedication... he's taught me that. I wouldn't have the fond memories without Craig Bellamy."

Having moved to the Roosters last year on a lucrative two-year deal, Cronk helped deliver the 2018 title by playing the entire grand final with a broken scapula, the type of injury usually seen in car crash victims.

It capped a nine-month period that saw Cronk replace popular clubman Mitchell Pearce, the 35-year-old still vowing to repay the Roosters investment in him as he eyes the final months of his career.

"To the Roosters, Nick [Politis], the board and [coach] Trent Robinson. This club has the reputation of living the high life but there's a lot of heart, a lot of selflessness in the Roosters emblem," Cronk said.

"I still don't know why they chose me. They chose me to have the two loves of my life here in Sydney. I thank them from the bottom of my heart for the part they've played in the past 18 months. I still don't think I've lived up to that."

Despite reports to the contrary over summer, Cronk denied considering retirement after his astounding push through the pain barrier.

"Never... at no stage did I ever consider that," Cronk said.

Cooper Cronk and Craig Bellamy celebrate the Storm's 2017 success.
Cooper Cronk and Craig Bellamy celebrate the Storm's 2017 success. ©Gregg Porteous/NRL Photos

"I'm a man of my word. When someone says you've got a two-year contract, that's my job. 

"It was hard. There's no doubt those first steps in pre-season were probably the most difficult of my time in that recovery.

"But I got back on the horse and I've got a job to do."

Cronk's retirement will free up the best part of $1 million in salary cap space at the Roosters next year.

Upgrading and retaining Test and Origin centre Latrell Mitchell is the club’s first priority, though it remains to be seen if he moves into the halves as Cronk’s replacement beside Luke Keary, or the Tricolours go to market.

Robinson conceded that replacing one of the best modern halves would be nigh on impossible.

"You don't fill a void like Cooper Cronk," Robinson said.

"You take the lessons from Cooper and you put it into the squad, not just the team but the squad. That's what we do.

“He came in 18 months ago and we knew were getting a top quality footballer. And then the man walked in and opened up straight away to each and every one of us and said ‘I’m here for you, what do you need’. He’s made me a better coach, pushed me as a coach.

"He’s the greatest team player I’ve ever seen."