Cameron Smith first started thinking about representative retirement during the 2017 State of Origin series.

He lay on the couch at home, mentally and physically spent, after another gruelling game.

It was these moments - when he felt like he couldn't back up for the Melbourne Storm or help with domestic duties - where his priorities became clearer.

Time to spend more time with family.

"Last year, finishing each Origin game, and returning home to my wife - I (remember thinking) just can't see myself playing this weekend for the Storm," he said.

"And those turnarounds were between three and four days, which every other year I've played is more than enough to get up for.

"I've actually looked forward to backing up for my club. That was the first sign.

"And then on top of that, when I wasn't playing for the Storm that weekend, I wasn't really offering much at home as a father and as a husband. I was either sitting on the couch or laying in my bed exhausted, both physically and mentally."

Is Cameron Smith the greatest ever?

Smith captained the Storm to a Telstra Premiership win last year. After a few days break, he then led the Kangaroos at the World Cup which also featured some pre-match games in Fiji.

"Maybe the length of that season - being away for three Origin games and then a six-week period for the Kangaroos confirmed for me that it was getting more difficult to be away from my wife and children," he said.

"My eldest now being 10 years of age - there's a few important things that are happening around my family with school and their junior sports, which I'm missing out on.

"That's a big commitment to make to miss those things, but it's a greater sacrifice for those guys. When you get your children asking why I can't be in attendance at some of their events, it's not a great feeling.

"I think it's a combination of the impact that representative football had on me and my family, was as a result of my decision."

Smith went to see Maroons coach Kevin Walters on Sunday in Brisbane after the double-header at Suncorp Stadium the previous night to inform him of his intention to retire from the representative arena.

It's understood Smith told his Storm teammates of his decision on Tuesday morning.

Apart from one match he missed in 2008 when Matt Ballin wore the No.9 jersey, Smith has not missed an Origin series since making his interstate debut in 2003.

Andrew McCullough, Jake Friend and Jake Granville would be the main contenders to replace him in the side to face NSW at the MCG on June 6.

Greg Inglis is the likely option to replace Smith as Queensland captain.

Inglis would be in contention for the Kangaroos captaincy but NSW skipper Boyd Cordner, who was vice-captain at the World Cup last year, would be the favourite for the national role.

Walters paid tribute to Smith at Tuesday's press conference.

"He's been a great player but even more a great person. Respect and humility - he shows that every day. One of the great things I respect about Cameron is how he conducts himself in every aspect of his life," he said.

"I take my hat off to you, mate. I think his performance in game three of last year's State of Origin series was one of the best I've seen of anyone at that level and he was at 34 years of age. To me, that speaks volumes again of the person and character that he is.

"I got a bit of an inkling earlier this year around a few discussions we had around State of Origin.

"I just didn't get the same vibe with his enthusiasm and drive around Origin. When he did tell me, it wasn't so much shock but it doesn't surprise me. Cameron is not a selfish person."

Cameron Smith retires from rep footy, who becomes @QLDmaroons new number 9? #Origin — NRL.com (@NRLcom) May 15, 2018

Smith's wife Barbara and children Jada, Matilda and Jasper watched on in a room that also included Storm CEO Dave Donaghy, Craig Bellamy and a number of club representatives.

The Storm captain was emotional when thanked his family for their support and he reserved additional praise for Bellamy for allowing him to chase his representative dreams.

He also thanked Wayne Bennett, Mal Meninga, Ricky Stuart, Michael Hagan and Walters for their involvement in his Queensland and Australian sides.

Smith leaves a legacy of excellence that started with an Origin debut in 2003 and ended with a World Cup win last year. His record of 42 Origins and 56 Tests for Australia are a testament to his longevity.

"What he's done for Queensland and Australia is nothing short of a miracle," Walters said.

"His performances through that time have been outstanding. He's set a benchmark for anyone who puts on the Maroon jersey during his tenure there."

Asked for a representative highlight and Smith listed his Origin and Test debuts. But other proud moments included the two World Cup victories in 2013 and 2017 as skipper and last year's Origin series win.

And with a grin and wave, Smith stepped away as the packed press gallery applauded his representative career.

Next stop? School sport and kids drop-offs.

Witness Australia's greatest sporting rivalry when Origin comes to the Melbourne Cricket Ground on Wednesday, June 6. Tickets available at NRL.com/tickets.