Born in Cwm, Spinetti was educated at Monmouth School and the Royal Welsh College of Music & Drama in Cardiff, of which he became a Fellow. After various menial jobs, Spinetti pursued a stage career and was closely associated with Joan Littlewood's Theatre Workshop. Among the productions were "Fings Ain't Wot They Used T'Be" and "Oh, What a Lovely War!" (1963), which transferred to Broadway and for which he won a Tony Award. Spinetti's film career developed simultaneously; his dozens of film appearances included Zeffirelli's "The Taming of the Shrew", "Under Milk Wood", "The Return of the Pink Panther" and "Under the Cherry Moon".