The centre-back beat Vicente Guaita (23%) and Jordan Ayew (8%) to claim the award after a solid month of determined performances.
Cahill played all 90 minutes in every February match bar Burnley, keeping a clean sheet against Fulham and putting his body on the line to ensure the Eagles could defeat Brighton & Hove Albion in the game's dying seconds.
He also claimed his first goal for the south Londoners by heading past Newcastle goalkeeper Karl Darlow, securing Palace three points in doing so.
"I'm very grateful and very pleased to get it so thank you very much," he told Palace TV after collecting the trophy.
"I'd rather not defend as much as we have in the last couple of games but at the same time it's pleasing when you do put the work in as a team collectively. As a team, we defended very, very well in the last few games and were rewarded for that with the Fulham clean sheet and win against Brighton, which I'm sure the fans enjoyed."
This is Cahill's second Player of the Month for Palace, having scooped the accolade in September 2019.
Hear more from Gary on his Player of the Month-winning February below!