Sheehan joined the Hatters, initially on loan, from Bradford City as Nathan Jones’ first signing in January 2016 – with the move being made permanent that summer.
His arrival was key in a change to a more expansive playing style with the ball-playing centre-half’s set-piece deliveries assisting many more goals than the nine he scored himself, mainly from spectacular free-kicks bent into the top corner of the opposition’s net.
The 33-year-old became a real crowd favourite at the Kenny, not to mention packed away ends at grounds up and down the country, with chants of ‘Sheehan, Sheehan’ a familiar cry as he captained the Town to successive promotions from League Two to the Championship.
In total, Sheez – as he is known to all at the club – made 135 appearances for the Hatters, including seven this season in league and cup. He was selected in the 2017-18 EFL and PFA League Two teams of the season, when he also won two of the Town supporters’ player of the year awards.
“Alan has been instrumental in the club’s success over the past four years, leading us up two leagues and arguably being responsible for captaining us to a level that at this time in his career has been challenging,” said CEO Gary Sweet.
“Huge respect has to go to him for his contribution on and off the pitch. We have all enjoyed watching that wonderful left foot deliver pinpoint passes, crosses and some quite brilliant goals, and as he progresses with his coaching qualifications, this agreement allows him to look to the future.
“Personally, I have always had an excellent relationship with Sheez. He’s a great lad who has been a leader for us on and off the pitch during some memorable times, and he leaves with an open door to come back as our guest at any time.
“On behalf of the board, the club and I’m sure the supporters, we wish him and his family the very best for the future.”
Manager Graeme Jones said: "Alan has been a top professional from the minute I came here. He was injured at the time, but I could see the pride he had in himself and his performance and his career.
"I don't think I've had Alan Sheehan in prime of his career, and even Alan will admit that. But what I have learned over the last few months is that he's a leader, a fighter, a winner who has had a huge influence over this football club.
"Me and him have got a fantastic relationship - very honest, very straight and I'll miss him because he's a really good, strong character. There's a bit of old school in him, and he is welcome back at this football club any time he chooses."
After saying his farewell to his team-mates and staff at The Brache this afternoon, Sheez said: “It’s been an unbelievable four years, definitely my favourite time as a footballer. That day at Notts County was a special one for me, going to take a corner and having both sets of fans singing my name in a party atmosphere. That is something I’ll never forget.
“The promotion from League Two was brilliant, with the style we did it in. Then the League One title win was unbelievable, losing the manager halfway through the season and Mick coming in, galvanising everything and keeping everyone together.
“It’s been a remarkable few years and I’ve loved being able to play in the Championship again after 11 years out of it.
“I want to thank everyone involved with the club – the players, staff, all the coaches and managers I’ve worked under here – and especially the fans. They’ve been unbelievable to me since the day that I came, right up to now, at a place I’ve really been able to call home. I feel I’ve had a special relationship with you and I’ve loved every minute.
“My final message to you all is to keep behind Graeme and the team. There’s an unbelievable spirit at this club and some fantastic boys in that dressing room. Please do everything you can to help them stay up.”
Thanks for the memories and good luck for the future, Sheez!