On his arrival at Buriram United, Cooper found the club in third place of the Thai Premier League, five points adrift of the league leaders. Under Cooper's managerial reign, Buriram were unbeaten in the Thai Premier League, AFC Champions League, Thai FA Cup and Thai League Cup.
Buriram United won 23 out of 29 matches, drawing five and losing only once under Cooper. The club won all their away games at the top four Thai clubs during the season. Named "Manager of the Month" in June 2013, Cooper led Buriram United to the top 10 club rankings in Asia, creating history for the Thai club in the process. Under Cooper's tutelage, Buriram on an average scored 3.1 goals per game whilst conceding 0.75 goals per game.
Cooper also had a major influence on developing Thai players in his squad, as nine Thai players were called up to the national team.
In June 2018, Cooper was appointed as senior team adviser of the Philippines (Interim).[6][7] Cooper was later tasked to oversee the national team's training camp in Bahrain in September 2018 in lieu of the newly appointed head coach Terry Butcher, who resigned from his post in August 2018.[8] Cooper's interim tenure ended in late August 2018 when he was officially named as the regular head coach of the Philippine national team.[9]
Cooper returned as manager in January 2019 after the conclusion of the Philippines' campaign in the continental tournament and Eriksson's short-term contract.[12] Under Cooper, the Philippines gained its highest ever World Cup point total.[13]
In May 2022, it was announced that Cooper stepped down as head coach of the Philippines men's national team.[14][15][16]