He initially gained attention as a quick-change artist, and later worked on stage, in films and in television, principally as a character actor in the United States.

[3] After the Second World War, McGiveney was invited by stage actor and comedian Ken Murray to appear in his popular revue, Blackouts, in Hollywood.

This move reinvigorated McGiveney's career, and he began working in the film industry as a character actor, making his first appearance in If Winter Comes (1947).

[2] He appeared in many films during the 1950s and 1960s, including Show Boat (1951), Scaramouche (in the role of Punchinello; 1952), Brigadoon (1954), Journey to the Center of the Earth (1959), and My Fair Lady (1964).

He also made a number of television appearances in shows including 77 Sunset Strip, Perry Mason, The Outer Limits, The Monkees, and Batman.