In the early 1970s, Grimes moved to London where he came to the attention of director Lindsay Anderson. Anderson offered him a part in his production of David Storey's play The Farm, the success of which established Grimes' reputation in British theatre.[4]
Grimes' most significant film role was the part of Major Fuller in Richard Attenborough's A Bridge Too Far (1977). However, he was probably best known, in his native Ireland at least, for his performance as Father O'Connor in RTÉ's drama series, Strumpet City. In 1981, Grimes received a Jacob's Award "for his detailed and exceptionally convincing portrayal" of the young priest.[5]
Frank Grimes continued to work in television, films and theatre throughout his later years. Later TV appearances included the recurrent role of Barry Connor in Coronation Street. In 2013 he appeared as Mrs McCarthy's husband in the Father Brown episode "The Mayor and the Magician".
Grimes died following a short illness on 1 August 2025, at the age of 78.[6][7]