He had a small role as an Australian prisoner of war in The Wooden Horse (1950), the third most popular film at the British box office in 1950. His performance as a Pole in Daphne Laureola led to his casting as a Polish soldier in The Miniver Story, the sequel to the wartime morale boosting film Mrs. Miniver; unlike its predecessor, it was poorly received critically.
Under the Big Top – touring show with George Sorlie, various Queensland towns, 1936, playing Herbert Hughes in Laughter of Fools by H.F. Maltby, Smithers in Married by Proxy by Avery Hopwood, Peter in Fair and Warmer by Avery Hopwood, Hunter in Ten Minute Alibi by William Armstrong – all directed by William McGowan with Murray Matheson, Rosalind Kennerdale, Leslie Crane, Eva Moss, Norman French, Julia Adair and George Douglas.
Finch's film roles increased in size and prestige through the early 1950s. For Walt Disney he played the Sheriff of Nottingham in The Story of Robin Hood and His Merrie Men (1952). He was given two good roles in films from Alexander Korda: as Richard D'Oyly Carte in The Story of Gilbert and Sullivan (1953), and as a priest in The Heart of the Matter (1953), from the Graham Greene novel.
During his war service Finch was given leave to act in radio, theatre and film. He appeared in a number of propaganda shorts, including Another Threshold (1942), These Stars Are Mine (1943), While There is Still Time (1943) and South West Pacific (1943), the latter for Ken G. Hall. He also appeared in two of the few Australian feature films made during the war, The Rats of Tobruk (1944) and the less distinguished Red Sky at Morning (1944).
During this time, Finch continued to appear on stage in various productions while under contract to Olivier. Finch's closeness to the Olivier family led to an affair with Olivier's beautiful but increasingly unstable wife, Vivien Leigh, which began in 1948, and continued on and off for several years, ultimately falling apart due to her deteriorating mental condition.