Atienza made his professional stage debut in the role of the Butler in a 1949 production of ''
Up in Mabel's Room. He went on to appear with the Shakespeare Memorial Theatre Company from 1950 to 1954. Atienza made his first appearance in London theatre in the role of Mole in Toad of Toad Hall'' at the
Prince's Theatre in December 1954. Atienza also appeared in productions of
Macbeth and
Romeo and Juliet on Broadway. He also was in the 1962 Broadway play
The Affair. British theatres at which Atienza has appeared include the
Queen's Theatre, the
Mermaid Theatre, and the
Chichester Festival Theatre. == Film work ==