Tom Scully will remain at GWS until at least the end of the 2021 AFL season.
Already signed until the end of 2017, the foundation player has signed a four-year extension at the club who he has helped propel into a likely finals position for the first time in their history.
"As someone who has been here from the beginning it was an easy decision to make and I'm excited about what lies ahead for the club both on and off the field," Scully said.
"I love this club and I love Sydney. I love playing football with my teammates and I love coming to work every day."
Scully's re-signing comes on the same days reports broke that he was set to give up more than $2 million to stick with the club.
The former Melbourne Demons player signed with the club on a $6 million six-year deal when he originally moved to the Giants, while this contract is only worth $500,000 a year in a bid to ease salary cap pressure according to News Corp Australia.