Aitken, 26, had already announced he would not head back to Auckland for the 2023 season and he won't have to move far at all, remaining in the same Redcliffe base the Warriors have played out of through the COVID period.
He joins a Dolphins forward pack that already includes Jesse Bromwich, Kenny Bromwich and Felise Kaufusi.
Aitken, whose deal with the Warriors was initially due to expire at the end of next season before he secured his early release, said his decision was about putting family first.
"If it was up to just me I probably would have gone (to NZ) and seen out the contract because I do like the club, it's got some great people and it's got some great people running the place," he told reporters.
"So there's definitely some fond memories here and it's definitely a hard decision to leave because there's definitely great people and it's going to go places in the near future."
Dolphins chief executive Terry Reader said the 143-gamer's experience would be vital in building the new club.
"Importantly, he is skilful enough to play either centre or on the edge at second row, and that is a valuable commodity in today's NRL competition," he said.
"He will also be able to bring some familiarity around our home base for our new squad after spending a full season training and playing there with his current club.
"Euan and the Warriors are currently three wins from three games at our home base of Moreton Daily Stadium this season – we hope he can see the same results with the Dolphins next year."
It's another blow to the Warriors' forward stocks having cut prop Matt Lodge last week, although they will gain Newcastle's Mitch Barnett in 2023.
They'll also be without Chanel Harris-Tavita, who will take a break from the game after this season.
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