The 30-year-old is now one win away from a grand final and will play in the preliminary final against the Sydney Roosters or Cronulla as one of the game's best in his position.
Reed Mahoney, now at North Queensland, inked a four-year deal to join Canterbury before his 2022 season with Parramatta had even begun.
Marshall-King was at the Bulldogs but didn't kick stones. Instead he played his backside off and was the club's 2022 player of the year, lining up in all 24 games while scoring five tries and averaging 39 tackles.
Mid-season in 2022 he inked a two-year deal with the Dolphins and was in the inaugural team the following year that beat the Sydney Roosters in round one.
"It was in my best interests to come here," Marshall-King said.
"They signed Reed Mahoney at the time at the Bulldogs and my best option was to come to the Dolphins and I'm glad I came,..
"I just wanted to give it a crack. I think I've done that so far and I will continue to build my game."
The Dolphins did well by signing experienced forwards Felise Kaufusi and Jesse and Kenny Bromwich early, with the trio proving to be magnets.
"The reason I signed here is because of Wayne (Bennett) and the players that were coming through. Fus is still here, but the Bromwich brothers ...I played Kiwis with them as well," Marshall-King said.
"I just wanted to learn from them and get the experience they've had in the game."
It was the players the Dolphins signed, not the ones they "missed out on" that have defined the club's success, but there were two other sliding doors moments that assisted Marshall-King.
The Dolphins were keen to sign Harry Grant as hooker but Melbourne informed his management weeks after the Dolphins won the licence in October of 2021 that they were taking up their option on him for 2023.
Then two months later, Brandon Smith, also with the Storm at the time, was close to joining the Dolphins but instead signed with the Sydney Roosters from 2023.
Marshall-King was clearly the better option and has proven his worth.
Despite several injury setbacks, he has stamped his class.
His guile, toughness and selfless play has also been rewarded with a return to the New Zealand side.
The Dolphins staged their eighth comeback by eight points or more this season to beat the Warriors 26-16 in the away qualifying final last week and give Marshall-King his first finals win.
"It was a pretty incredible experience," he said.
"It's taken me a long time to get there and I just pretty much soaked it in and enjoyed that moment, especially back home in New Zealand. It was something special."
Marshall-King said he was "absolutely" backing the Dolphins to win the premiership.
"I think the biggest thing for us is our connection as players and we don't want to let each other down in any way," he said.
"We just want to keep working for each other. You don't want to come into video regretting stuff and thinking, ' I could have done better'."
Coach Kristian Woolf is driving that ethos.
"He has given me the confidence to play my game," Marshall-King said.
"Outside of footy he cares about you as a person and your family as well, and that means the world to me."
