During the 1950s and 60s, O'Shea was New Zealand's only feature film producer. Against the odds, he pioneered films that not only explored the New Zealand character, but also dared to confront New Zealander's with their own racism. On returning from the war, O'Shea began work as a historian and film censor. In 1950 he met Roger Mirams, a young newsreel cameraman and together they made Broken Barrier. The film premiered at the Regent Theatre Wellington on July 10th 1952, attended by the Governor General Lord Freyberg, the first of many who flocked to see New Zealand's first full length feature film. Although well received in New Zealand, the film failed to sell overseas. With no funds for another feature film they turned to making Movietone News items.

In 1956 Roger Mirams left Pacific Films and moved to Australia. In 1961, with the beginning of television broadcasts, there was a need for Pacific Films to produce television commercials. Their first was for Jockey's underpants and featured Peter Harcourt . Tony Williams explains the voice over, 'What does the well dressed man wear next to his skin and 'ping' all the clothes popped off Peter, leaving him in his underwear.' The commercial was banned!

For his services to the New Zealand film industry John O'Shea has received an O.B.E. and Honorary Doctorate and a Lifetime Achievement Award from The New Zealand Film Commission. At 73, O'Shea continues to add to his Pacific Films Collection currently being preserved by The New Zealand Film Archive.