After leading Geelong to two AFL premierships in three years, Cats skipper Tom Harley has hung up his boots, leaving behind a legacy as a new-age captain.

His body exhausted after five knee operations, the 198-game defender decided to bow out a month after the grand final triumph over St Kilda.

Harley, 31, drew extraordinary accolades from coach Mark Thompson, who called him "one of Geelong's greatest captains", and chief executive Brian Cook.

Cook described Harley as a revolutionary club leader whose positive influence had reached out beyond the playing fields and into the community.

"What Tom has brought is a new style of captaincy where, while he represents the view of the players, which is his role, he's an extension of coach-thought, of director-thought, of staff-thought," Cook said on Thursday.

"And he balances up the stakeholders really well - it's a new type of captain and for that we owe (him)."

Thompson said Harley's strengths were in being able to pull the playing group together and "the way he represented the club, the wider public, our supporters".

"I think Tommy's set a new set of rules, a new way of showing the players at the club currently how to be a captain," Thompson said.

"I don't think they really had an example as good as what Tommy set for them."

Harley was more modest, saying he was just happy to "play a part".

"Other people will determine how significant that part was and I don't really know to be honest," Harley said.

"I feel like I've seen all spectrums (of the club) - we were average, we were good, we were okay, then we were excellent so to have been involved in all those generation shifts is probably what I'll take from it."

It has been a massive month for Harley after his grand final triumph and his marriage two weeks ago to Felicity Percival, who he described as "my rock".

But the issue of retirement had been unavoidable following the Cats' premiership this year.

Thompson had offered to allow Harley to play on next season so he could reach the coveted 200-game mark.

"I seriously thought about it and was honoured to be offered that opportunity but sometimes there's just good timing and I thought this was my time," he said.

"I had my chance to play 200 games this year (he played just 11 due to injury) and just couldn't do it. That's life."

While Cameron Ling is expected to succeed Harley as captain, he would not be drawn on the subject, saying the club had a "plethora of candidates."

Apart from the grand final victories, Harley singled out his 100th game as being one which stood out, a match he played alongside fellow backman Matthew Scarlett.

"It was 2004, we were a young side and we played against Essendon - it was myself and Scarlo versus (Matthew) Lloyd and (Scott) Lucas that day.

"Both played really well and to share that milestone with Scarlo was massive.

"I'm not a huge memorabilia collector but I've got my 100th game jumper signed by both me and Scarlo."

Harley said he wanted to stay involved with Geelong but virtually ruled out a coaching position at a rival club because of his deep attachment to the Cats.

"I can honestly say there's nothing in concrete with anything really," he said.

"As of eight days time I'm unemployed.

I just want to sit back and smell the roses for a bit and see what pans out."