Following the end of the Second World War, United rejoined the Irish League for the 1946-47 season, with Billy Reid appointed as manager at the beginning of May. However, he only lasted in the job until the end of October when he resigned, being unable to dedicate enough time to the management of the team, and the club resorted back to using a selection committee. The first competitive match after the war was a 2-1 victory over Distillery in the Gold Cup at the Ballymena Showgrounds.
Ballymena started the 1947-48 season with newly appointed manager, Bob McKay who was promoted from his role of chief scout, and he also had previous experience of management in the form of Dundee United. McKay managed to lead the sky blues to a third place finish in the league. An Irish Cup defeat against Linfield saw an attendance of 9,067 in the first round, after which Frankie Houghton departed to Newcastle for the sum of £6,000.
April 1948 saw United’s first competitive match outside of Northern Ireland, as they played Shelbourne of Dublin in the Inter-City cup. They travelled south of the border with a 4-1 lead from the first leg and progressed to the quarter final stage despite losing in Dublin, winning 4-2 on aggregate, where they crashed out to Shamrock Rovers losing 8-3 after the two legs.
Ballymena did win a trophy that season, however, in the form of the County Antrim Shield, beating Linfield 2-1, bringing the trophy to the Showgrounds for the first time in the club’s history.
Any optimism gained during that season was quickly quashed the next, as United fell to a disappointing tenth placed league finish and failed to make much progress in any of the cup competitions. McKay lost his job at the AGM following the season, as he accused board members of interfering with his team selections.
Norman Kernaghan was appointed as player-manager to replace McKay and in the 1950-51 season, Kernaghan’s second in charge, the club again won the County Antrim Shield, this time beating Cliftonville in the final, as well as reaching the final of the Irish Cup.
The following season the club achieved what they have found to be a hard task to manage, winning silverware for the second season running, a feat they have managed only one other time in their history. They won the Festival of Britain Cup, which was a one off tournament in place of the Ulster Cup, beating Crusaders 3-0 in the final in May 1952, with the trophy remaining in the Ballymena Showgrounds.
The club went through another lean spell after this season, though, and in 1955 the club launched an appeal asking for help clearing the clubs debts, the people of the town responded generously, and the club was able to clear their debts and still had a surplus to be kept by the club.