“I feel I have plenty to offer the club and I am committed to helping to grow and develop our young playing list,” Geary said.
“I am very proud to be a part of the St Kilda Football Club. The club has been great to me right throughout my career and I never seriously considered any option other than staying a Saint.”
Geary has played 100 games since joining the Saints as a rookie in 2007.
He finished four in the club’s best-and-fairest last year.
Saints head of football Chris Pelchen lauded Geary leadership qualities.
“We are very pleased to have completed a contract extension for Jarryn,” he said.