Tuohy, 34, will hang up the boots at the end of the finals campaign after more than 280 games with the Cats and Carlton.
Tuohy told his teammates of his decision on Tuesday and announced it in a video statement to Geelong members on Wednesday
"While there's a lot of footy left to play this year, I just wanted to take this opportunity to thank you all for your support," Tuohy said.
"I knew when I came to the Cats I was in for a treat. I don't think I fully appreciated just how much of an incredible journey it was going to be.
"There's a lot of work left to do this year but I just wanted to thank you for everything.
"Geelong, the club and the city, has been incredible for me and my family.
"I consider myself a Geelong person forever off the back of your support.
"A lot of work left to do - I look forward to seeing everyone this weekend - but 2024, that'll do me."
What a ������ Ride 🌊 — Geelong Cats (@GeelongCats) #WeAreGeelong pic.twitter.com/7xH6DxovyOAugust 21, 2024
Tuohy attracted attention from AFL recruiters in 2009 and was lured by Carlton out of Portlaoise in County Laois in 2010.
He became an accomplished defender and moved to Geelong at the end of 2016, before featuring in the Cats' 2022 premiership alongside fellow Irish player Mark O'Connor.
The pair were the second and third Irishmen to win premierships after Sydney's Tadhg Kennelly (2005).
Tuohy is only the second Irish player to play more than 200 AFL/VFL games and passed the late Jim Stynes' record of 264 appearances last year.
He will play his 287th game when the Cats host West Coast at GMHBA Stadium on Saturday.
Zach Tuohy is chaired off the MCG after Geelong's 2022 flag win. (Joel Carrett/AAP PHOTOS)
"Zach has been a skilful, durable and flexible player across his eight seasons in the hoops," Geelong football manager Andrew Mackie said.
"He will depart as the Irish games record holder, which is a remarkable achievement for someone who made the decision 15 years ago to leave home to travel across the world to play our game.
"He is a loved and respected teammate and has contributed greatly to the environment of our club."
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