Now attention turns to who will take his place on the morning talk show alongside Amanda Gillies and Mark Richardson.
Could it even be Richardson stepping up to host the show? He is high-profile as the host of The Block NZ but he lacks a journalism background and the breadth of skills to interview across a range of subjects.
A statement this morning from Three said Garner's departure was effective immediately, and that an announcement will be made regarding his replacement "in due course" - so who might be taking his place on the talk show?
Ryan Bridge. Photo: Magic Talk
Ryan Bridge
The statement from Three said that Magic Talk host Bridge would host The AM Show this week until a replacement could be found.
But it's not the first time Bridge has filled in for Garner, leading some to speculate he'll move into the role permanently.
Prime News presenter Eric Young. Photo: Supplied
Eric Young
Newshub's Oriini Kaipara. Photo: Supplied
Oriini Kaipara
Newshub's Oriini Kaipara, formerly of TVNZ, made headlines when she became the first person with a moko kauae to present mainstream television news.
Having already made the move to Newshub from TVNZ earlier this year, she would be a long shot to replace Garner on the morning talk show.
Paul Henry did not wish to comment on Garner's replacement. Photo: Supplied
Paul Henry
The AM Show was created to fill the void left by Paul Henry when he departed Three (then TV3) in 2017.
Now some are speculating whether the broadcaster will return to the network.
When contacted by the NZ Herald, Henry would not comment on whether he'll take Garner's place.
Newshub political editor Tova O'Brien. Photo: MediaWorks
Tova O'Brien
Newshub's high-profile political editor Tova O'Brien is known for being a relentless interviewer - and last year she went viral after her brutal interview with disgraced National MP Jami-Lee Ross, calling him to account over Covid-19 misinformation.
Her interviewing style might be just what the network is after for The AM Show. She has also added presenting experience as a co-host of Newshub Nation.
Newstalk ZB host Marcus Lush. Photo: Supplied
Marcus Lush
The Newstalk ZB night host and Invercargill city councillor's name is already being floated on Twitter as a potential replacement for Garner.
Sean Plunket. Photo: Twitter
Sean Plunket
No one has put forward Sean Plunket for the job, but he has put his hand up with his tongue firmly in his cheek, posting this on Twitter:
Plunket announced his departure from Magic Talk and Mediaworks in February this year after a two-year stint on the radio show.
It came after he voiced his support for radio host John Banks, who endorsed a caller's view that Māori were a "stone-age people with a stone-age culture".
