FIFA referee between 1956 and 1970, Leo Callaghan took charge of a match in the 1966 World Cup. He is also one of the few Welshmen to have officiated a FA Cup final. (in 1968).
Callaghan was also active in European Cup matches and European international qualifying rounds.
After his retirement in 1971, Leo became Football League assessor (whatever profound work that may be). Leo Callaghan died in 1989.