He helped Bruce Rioch's side to win promotion at the end of the season after a second-place finish in the Third Division.
Kerr also managed to get some revenge over Aston Villa by scoring past them in the 1990 Full Members Cup semi-final, which helped Middlesbrough reach Wembley for the first time in the club's history.
He was an unused substitute in the final, as "Boro" lost 1–0 to Chelsea following a first-half strike from Tony Dorigo.
However, Kerr departed Ayresome Park in March, having scored 18 goals for Middlesbrough in 162 appearances in all competitions.
In March 1991, Kerr was signed by Bruce Rioch for a second time, who was then in charge at Millwall and authorised a fee of £100,000.
[5] The "Lions" went on to finish the season in the play-offs places, only to lose to Brighton & Hove Albion at the semi-final stage.
Kerr signed for Port Vale in July 1992, with manager John Rudge paying a reported fee of £140,000.
He joined Martin O'Neill's Wycombe Wanderers on a week-to-week contract for the 1994–95 campaign and scored one goal in his only substitute appearance in the league; he also started one cup game for the club.
He collapsed in front of O'Neill, and a subsequent medical examination showed he had spinal damage and needed to retire.