The 35-year-old has been without a club since leaving boyhood side Sunderland in May and revealed his intentions to step away from the professional game via his social media account early this morning.
Described as a “modern day Boro great” by the Boro club website, Leadbitter made almost 250 appearances during a six-and-a-half-year spell on Teesside after joining on a free from Ipswich Town in May 2012.
Leadbitter quickly became a crowd favourite at the Riverside Stadium after being named Player of the Year in his first season with the club before playing a pivotal role in the club’s run to the Championship play-off final in 2015 and their historic return to the Premier League in 2016 under Aitor Karanka.
Success with Boro was Leadbitter’s second promotion to the top flight after helping the Black Cats achieve the same feat in 2007 under boss Roy Keane having come through the ranks on Wearside.
Speaking via Instagram, Leadbitter posted: “The time has come to officially end my days playing professional football.
“After taking a few months off to enjoy a holiday with the family and reflect, I’ve realised I am ready to retire.
“Of course there has been a temptation to carry on, but since playing my final game for Sunderland in May I have had it in my mind I wasn’t going to play on. I just wanted to be sure it was the correct decision.”
Leadbitter, who featured regularly for England Schoolboys up until Under-21 level, went on to thank his family for helping him to “fulfil a dream,” before acknowledging the achievements he has made, particularly in the North East.
“The memories I have from playing for Sunderland, Middlesbrough and Ipswich will live with me forever. Those promotion celebrations with Sunderland and Middlesbrough were incredible and I am proud to have played in the Premier League for both.”
Middlesbrough acknowledged their former midfielder’s retirement with a video of Leadbitter’s “Top 10 Magic Moments” at the club including a number of trademark long-range goals while Sunderland referred to one of their own simply as “Legend.”