After Heeney had a breakout second season in the AFL, Sydney made his signature a major priority this off season, with the blonde-haired midfielder considered a key piece in the club's playing future.

Just last week the Swans announced star midfielder Josh Kennedy had also committed his long-term future to the club, joining Kieren Jack, Nick Smith, Luke Parker and Gary Rohan among others to pledge loyalty to the club.

"We're rapt that Isaac has agreed to terms on a new five-year contract extension and has committed to the club for the long-term," head of football Tom Harley said.

"Isaac is clearly a talented player who has played some high-quality football so early in his career."

The 20-year-old from Newcastle has been a mainstay at the AFL club since his 2015 debut in which he kicked the match-sealing goal against Essendon

He won the club's Rising Star award that year and played in 14 games before adding another 24 to his log in 2016.

Heeney claimed the AFL Coaches Association's Best Young Player of the Year Award that year.

With AAP