Massey began to conquer audiences on the other side of the Atlantic when he played one of the leading roles in the Broadway musical, "She Loves Me" (1963). With his dapper appearance and polished, actorly flair, he again invoked his stage origins in his most acclaimed US film performance, as his own godfather in the otherwise disappointing biopic of Gertrude Lawrence, "Star!" (1968). Massey upstaged Julie Andrews in his carefully realized and slightly parodic rendition of Coward and won himself a Best Supporting Actor Oscar nomination. Subsequent films included biopics ("Mary, Queen of Scots" 1971, "The Incredible Sarah" 1976) and courtroom drama ("Scandal" 1989; "In the Name of the Father", as the prosecuting attorney, 1993). Massey also showed a fondness for old-fashioned entertainment with the fun horror fare of "Vault of Horror" (1973), in which he acted opposite his sister, and the likable remake, "The Cat and the Canary" (1979). His fop was but one memorable item in Nicholas Roeg's obsessive "Bad Timing" (1980).
In between stage work, Massey worked in TV ranging from fine PBS adaptations ("The Roads to Freedom" 1972, "The Golden Bowl" 1973) to offbeat turns in eclectic fare. He played Trotsky in HBO's "Stalin" (1992), romanced Marilu Henner in "Love With a Perfect Stranger" (Showtime, 1986) and was moving as an AIDS sufferer in "Intimate Contact" (HBO, 1987).