The 25-year-old was locked in until the end of 2027 but will be on the books until the age of 33 after putting pen to paper on an enormous seven-year contract extension on Tuesday.
The Dockers wanted to ensure that, with Tasmania set to enter the AFL competition as its 19th team in 2028, Serong would not be available as a free agent come the end of the 2027 season.
Serong has become the second player in the competition to be locked into a deal until the end of 2034, joining Melbourne's Kozzie Pickett.
Fremantle have not hidden their ambitions to lock in a long-term core and build a successful dynasty, already having signed several players into the next decade such as Josh Treacy, Andrew Brayshaw, Patrick Voss and Hayden Young among others.
Serong said in a club release that securing a long-term future with an already familiar playing group made his decision to commit easy.
“It's very, very exciting, one of the parts that gets me going in the morning is the passion and the excitement those guys - and such a big group of our cohort at the moment - have for this footy club,” Serong said.
“You don't commit that long to a footy club if you don't have an emotional and a really strong investment with that, and that's what I feel the most.
“I feel that emotional, strong love for this footy club, and I know a lot of those guys do too.”
“It's a great feeling to be able to commit long term and to know what our future looks like as a family, where we're going to be for the next nine years now, which is really exciting and something that didn't require too much thought.”
Fremantle executive David Walls said that the Dockers are "absolutely thrilled" to get Serong's lifetime commitment.
“The individual accolades he has, alongside the leadership qualities he consistently demonstrates year on year, are pretty incredible given he’s still just 25," Walls said.
“It’s great to see him locked away as a Fremantle player and a member of the Freo family for life, essentially.
“He was going to be out of contract and a free agent at the end of next year, so with Tasmania entering the competition and a number of other Clubs interested on the east coast, he would have certainly been one of the most sought-after players.
“Caleb’s signature is great news and just shows that he and his now wife Chloe, are Freo through and through. They’ve fallen in love with WA since moving here from Victoria and well and truly believe in what we are building at the club.”