The 22-year-old was reportedly targeted by Greater Western Sydney during trade discussions for Jeremy Cameron, but he had no intentions of departing the Cattery.
His new deal was made official on Monday and will take him through until the end of the 2022 season.
Parfitt established himself in Geelong's strong midfield with his 107 tackles, ranked the second most across the AFL in 2020.
"Brandan is an integral part of our future, so we're pleased to have secured him until the end of 2022," General Manager of Football Simon Lloyd said.
