"I felt really good while I was at training, I was training really hard. Away from footy, when I was at home it was a different story for me. I felt a different way.
"I spent hours and hours and sleepless nights trying to find a way for me to brush it aside and to play on.
"My heart was telling me that I wanted to play on and my mind and my head was telling me otherwise.
"This hasn't been an easy decision for me to come to, but it's the right one."
Cordner then broke down in tears while thanking Roosters coach Trent Robinson.
"Apart from my dad he's had the biggest influence on my footy career. I can't thank him enough for what he's done for me as a player, but as a person as well," he said.
"The trust, the care, the love, the loyalty, the confidence, the belief, I've felt all of that, and I want to thank you so much. You're the leader of this club.
"I can't thank you enough for what you've done for my career … not as a player now but as a friend."
Cordner represented the Roosters in 183 NRL games since making his first-grade debut in 2011. He won three premierships with the club in 2013, 2018 and 2019.
The star forward played 16 State of Origin games for New South Wales, captaining the Blues to consecutive series wins in 2018 and 2019.
Cordner also represented Australia in 20 Test matches, captaining the national side since 2018.
Roosters Chairman Nick Politis said in a statement: "Boyd should be very proud of all his achievements throughout his career.
"Boyd's name will always be synonymous with the Sydney Roosters."
Robinson called Cordner "one of the greatest leaders of men I have seen".
"At any level of the game, I'm sure that every player who ever stood alongside Boyd would thank him for being the teammate and leader that he was," Robinson said.
"Boyd has been an incredible player and leader for the Roosters and I've loved coaching him."
Speaking on SEN 1170 Breakfast, Melbourne Storm icon Cameron Smith declared Cordner had made the right decision.
"He's still a young man, he's only 29 and he's got a lot of time left in his life," Smith said on Monday morning.
"Of course rugby league has been a huge part of his life up to this point, but there's plenty of years to come for him to share with his friends and family.
"It is a shame because he's one of the great players and has been for some time now and he's a lovely fella, I can't speak highly enough of Boyd Cordner.
"I got to play numerous games alongside him in green and gold, and I always thought he was one of the great people of rugby league.
"It's a wonderful, decorated career that Boyd's had, it is unfortunate that it's been cut short, but he's done more than most and he should be very proud of what he's achieved and what he's contributed to the game of rugby league."
