At 24 years old, Callum Mills is comfortably the youngest skipper in the AFL.

Sure, he's 25 in April.

But even then, he's two calendar years shy of Western Bulldogs skipper Marcus Bontempelli, St Kilda captain Jack Steele, Carlton's Patrick Cripps and the Giants' Josh Kelly.

In fact, the only skipper that comes close to Mills in the birth certificate department is newly anointed Gold Coast skipper, Touk Miller. He was born the year prior to Mills in 1996.

With Dane Rampe and Luke Parker also shouldering the captaincy load at the Swans in 2022, the young midfielder won't have to navigate his elevation on his own.

But Mills nonetheless understands the significance of his new title, particularly when it's at the exclusion of three-time club best and fairest and premiership star, Josh Kennedy.

"For Joey to step down, to let me come through, it's just really selfless," Mills told AFL.com.au.

"I'm really grateful to be honest.

"It has been a smooth transition and I'm really looking forward to the season getting started."

While some clubs baulk at even the suggestion of co-captains, Sydney has embraced multiple leaders with great success.

In 2005, the red and the white opted for three captains in Barry Hall, Brett Kirk and Leo Barry. It would be the year the club broke their 72-year premiership drought.

Since then, only in 2017 – when Kennedy was the sole skipper – have the Swans opted against co-captains.

Mills says he's honoured to join the likes of Hall, Kirk, Barry, Adam Goodes and Jarrad McVeigh.

But the captaincy hasn't quelled his desire to become a better player and leader.

"I've always strived to be the best leader I could be and I guess the result of that is the captaincy now," Mills said.

"I'm really grateful and honoured to be a captain at a young age.

"I think (my teammates) like what I'm doing, the way that I'm leading and what I do on the football field.

"The important thing is not to rest on that and to keep on continuing and building trust within the group."

Mills has all but cemented his spot in coach John Longmire's midfield, after starting his AFL career in defence to great fanfare in 2016, when he won the NAB AFL Rising Star.

Despite only playing around half of Sydney's pre-season match against the Kangaroos as he recovers from an Achilles injury, he remains confident he'll be ready for the club's Round One encounter against the Giants at Accor Stadium Australia.

"It's just continuity of doing the right load," Mills said.

"It's super fickle but hopefully we've managed to get a hold of it and it's set for the season."