Ronalds first professional role was in Oscar Wilde's An Ideal Husband (1950) in repertory at Worthing. He was in The Square Ring at Hammersmith.
He had uncredited bit in Valley of Song, set in Wales. He was credited for the film version of The Square Ring (1953), for Ealing; The Beachcomber (1954), as a native islander; The Face of Love (1954) for the BBC; and Fantastic Summer (1955) for TV. He had a larger part in Helen of Troy (1955) as Aeneas.[2] and provided some romantic interest in The Prisoner (1955), with Alec Guinness.