The AFL's equal longest-serving coach, John Longmire, is quitting as Sydney Swans coach after 14 seasons but staying at the club in a new role.

Longmire joined Sydney in 2011 and under his leadership the Swans made the grand final five times.

However, they only won once, in 2012, and Sydney's 60-point thumping by Brisbane in this year's decider was demoralising for the club.

It was Sydney's second big grand final loss in three years.

An emotional Longmire said farewell at a press conference alongside Swans chairman Andrew Pridham and new Swans coach Dean Cox.

Pridham praised Longmire as the longest-tenured coach in the club's 150-year history. He said Longmire had come to the club 18 months ago and said he wasn't sure if he could make it to the end of his contract at the end of 2025.

A succession plan was then established.

Longmire said he and the club's executives came to put any decision back until the end of 2024. He told the media he didn't know when he coached the 2024 grand final that it was going to be his last game.

"I didn't know at that point — sometimes you need a bit of time to work it out.

"All I know is halfway through the year I was talking to Tom (Harley) and Andrew (Pridham) about it, I wasn't quite sure. I felt I needed to stop and rest and reset and it's hard to do that when you're coaching," he said, adding that he might have made the decision to step down quicker if the Swans had won the grand final.

In the end, he said: "I felt like the best thing to do for the club would be to hand over to Coxy."

He paid tribute to the club, the executives, the players and the fans.

"I want to thank our supporters, who have been absolutely fantastic, so supportive of me and the team and those who have supported for so long too. This year was another level (from the fans), I’ve never seen anything like it."   

Cox takes over on a four-year deal after being Longmire's assistant since 2017.

"Thanks for the opportunity to coach this amazing football club. I understand it’s a huge responsibility," he said.

"To John, to have an impact like you’ve had is profound, I have seen that first hand. You’ve left a huge footprint on this football club.

"Hopefully I can continue to make you proud (as coach)."

The decision completes Cox's transformation from a West Coast Eagles great as a player, to an assistant coach of the Eagles' great rivals, now to leading that club.

"Seven years ago when I came here as an enemy [of the Swans] for so many years, to be part of the (Swans) family ... I will be forever grateful," he said.   

Longmire will stay at the club, moving to a new position as executive director of club performance, looking at strategies and high performance on and off the field.

"I've always been interested in the strategic areas of the club's growth, and as time has gone on, I've felt myself being drawn more and more towards this aspect. After a bit more time to rest, I'm looking forward to helping the club on its path of continuous improvement both on and off the field," Longmire said in the club statement earlier in the day.

"It would have been nice to finish with a flag, as I did as a player, but that wasn't to be."

Longmire's departure means Geelong's Chris Scott — who began his time in charge of the Cats the same season as Longmire in 2011 — is now the longest-serving coach in the league.

Longmire played 200 games of VFL/AFL football for North Melbourne.

He won the Coleman Medal in 1990 with a tally of 98 goals, and won a premiership in his final game for the Kangaroos in 1999 before embarking on a coaching career.

He took over in Sydney from Paul Roos in 2011 and has maintained the level of consistent results at the club, with the Swans making finals in 12 of his 14 seasons.

His overall record in charge was 316 games coached for 197 wins, 116 losses and three draws.

However, there were concerns given Sydney's last four grand final appearances resulted in losses — to Hawthorn (2014), the Western Bulldogs (2016), Geelong (2022) and Brisbane (2024) — by an average of 56.5 points.

Unlike a lot of other clubs, Sydney has chosen to make internal appointments for the top coaching position, with Longmire taking over from Roos, who was an assistant coach under Rodney Eade before the latter's resignation in 2002.

Roos took over as caretaker coach until the end of the season, when he was given the permanent position, where he stayed for the next eight seasons.

The Swans will now have a permanent coach in place for the start of the 2025 season.

Cox, a premiership ruckman with West Coast, has been an assistant under Longmire since 2017 and was mentioned as a potential successor to Adam Simpson as Eagles coach.

But he ruled himself out of the running, saying he and his family were settled in Sydney.