The speedster crossed from Sydney to the Cats last season and made an immediate impact, booting 25 goals in 19 games.
The 28-year old has totalled 125 AFL games after making his debut in 2010, booting 121 goals over that span.
“Gary was able to enjoy a strong start to his career in Geelong colours at the beginning of the season. He made a smooth transition into our team and was an energetic addition to the group both on and off the field,” Geelong’s general manager of football Simon Lloyd told the club website.
“Since arriving 12 months ago, Gary, his wife Amie and daughter Bella have been a welcome addition to the club, as a family they have embraced everything about the community of Geelong.
“We are pleased to have secured Gary’s services for a further two years and look forward to what he can bring to the team.”