SYDNEY star Isaac Heeney has turned his back on free agency to sign a huge six-year contract extension that will keep him at the club until the end of the 2028 season.

The 25-year-old is fresh off a dominant season in 2021, kicking 36 goals from 21 games including four in Sydney's elimination final loss against Greater Western Sydney.

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Heeney was set to become one of this year's hottest free agents, joining the likes of fellow 2014 draftees Jordan De Goey, Darcy Moore and Angus Brayshaw as first-timers on the list.

The forward-turned-midfielder said he was "over the moon" to sign the deal.

"It's the club I grew up barracking for and to be a one-club player here at the Sydney Swans is incredibly humbling and extremely exciting," Heeney said.

"The bond we have at this club, from the players to the coaching staff, we're all one unit.

"We ride the highs and lows together, and how we stick together is a reflection of the Bloods culture.

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"I'm determined to help this club achieve that ultimate success. Losing the 2016 Grand Final makes you appreciate how hard it is to get there on the last day of September, and how much I really want it. Over the next six years that is my biggest goal."

A product of the Swans Academy, Heeney made his debut in 2015 and won the club's Rising Star award as well as the AFL Coaches Association Best First Year Player.

In 2016, Heeney won the AFL Best Young Player award, took out the 2018 AFL Mark of the Year and was twice selected in the AFL Players' Association's 22Under22, in 2017 and 2018.

Co-captain Luke Parker told AFL.com.au recently he believed Heeney could become a midfield headache for opponents in 2022 and beyond.

Parker said Heeney's contract had never been a topic of conversation among the players.

"He just enjoys his footy, he lets that do the talking," Parker said.

"We don't get caught up in the off-field stuff at this club, maybe some little jabs amongst the boys, but all in good fun."

GM of football Charlie Gardiner said he was pleased to see Heeney commit his future to the red and white.

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"Isaac is a special player whose hard work and dedication has seen him develop into one of the best talent's our club has seen," Gardiner said.

"He is an enormous competitor, driven to improve year on year and we're confident his best is still to come. Isaac's long-term commitment to the club is testament to his love and passion for the club, his coaches and his teammates. I know his focus is squarely on helping the team get better and delivering ultimate success."