In 1974, Dunstable Town received the financial backing of Keith Cheesman. He hired a young Barry Fry as manager, and gave him money to build up a strong team; indeed in his autobiography, Fry claims that he was often given blank, signed cheques. Of note, both Jeff Astle and George Best were brought in to play for the team with Best playing two pre-season games to promote interest in the club. Dunstable were promoted under Fry, but he was later dismissed by Cheeseman's successor, Billy Kitt, after a poor performance in the Southern League.
After spells at Hillingdon Borough and hometown club Bedford Town, in 1979 Fry became Barnet manager for the first of two management spells covering almost thirteen seasons. In his first spell, Barnet maintained a mid-table position in the Alliance League for six seasons before Fry left in December 1985 to manage Maidstone United. He returned to Barnet in August 1986 for a further seven seasons. Three times runners-up in the GM Vauxhall Conference, Fry achieved his first managerial success as Champions in 1990–91. Two years later he guided them towards the new Division Two (leaving two months before the end of the season to manage Southend) despite being sacked eight times and reinstated each time by controversial chairman Stan Flashman, as well as being in charge of a club which was in a precarious financial state and under threat of expulsion from the Football League.
Fry moved to Southend United in 1993 with the club bottom of Division One. Fry kept Southend up, but later in the year moved to Birmingham City. Though Birmingham were relegated in his first season, he won the Division Two championship in 1995 and also reached the finals of the Football League Trophy. During the 1995–96 season, Fry guided the Blues to the semi-finals of the League Cup but was sacked after their mid-season promotion hopes faded and the club finished 15th in Division One.
Just after leaving Birmingham, Fry became chairman-manager of Peterborough United. They were relegated to Division Three in his first season at the helm but they regained their Division Two status three years later. Fry's nine-year reign as manager came to an end in May 2005 after they were relegated again, after which time he took up a role as director of football. Fry remained as chairman until September 2006 when Darragh MacAnthony succeeded him.
Fry's prolific and often erratic dealings in the transfer market led to lifelong Birmingham City supporter Jasper Carrott claiming Fry "was probably trying to sort out the unemployment problem single-handed!"
Fry was often renowned for his attacking brand of football, although his tactics often meant his teams conceded more goals than they scored.
Fry starred in a documentary called There's Only One Barry Fry. The programme included some of Fry's dressing room antics, including a row with Mick Bodley and his promise to get the Posh out of Division Two. Fry's Peterborough United were later the subject of Sky One's 2006 documentary series Big Ron Manager in which Ron Atkinson was bought in as a troubleshooter to help Fry and the management team during Peterborough's quest for promotion. They finished 10th.