Versatile Sydney youngster Harry Cunningham has signed a three-year contract extension, keeping him at the Swans until the end of the 2019 season.

The 22-year-old was selected by the Swans with pick No.93 in the 2011 Rookie Draft after being overlooked by the GWS, despite being part of the Gaints' academy.

Cunningham has since repaid the club's faith, establishing himself as a regular in Sydney's line-up, missing just three games since the start of 2014, for a total of 56 games in five seasons.

"I could have been a Giant, but I'm happy where I am," Cunningham told AFL.com.au.

"I am absolutely stoked to be able to re-sign and stay here for an extra three years.

"I owe a lot to the Swans and hopefully I can repay their faith over the next three years."