As a young child Ney went with her family to live in New Zealand. She began her acting career in that country and continued it in Australia. After several years of performing in those two countries she moved back to Britain, where she acted at the Old Vic with many famous actors of the day such as Michael Redgrave and Robert Donat. In 1930 Ney played Lady de Winter in the musical The Three Musketeers at the Theatre Royal, Drury Lane in London.
Ney's first film appearance was in Desert Gold (1919), a silent film made in Australia. She appeared in 11 films during the 1930s, including The Wandering Jew (1933), Scrooge (1935), Brief Ecstasy (1937), Jamaica Inn (1939) and A People Eternal (1939). In 1941 Ney returned to Australia for a six month season, appearing in the plays No Time for Comedy, Noël Coward's Private Lives and Ladies in Retirement in Sydney and Melbourne. She appeared in the 1948 play Rain On The Just in London and in 1959 The Last Word at the Royal Lyceum Theatre in Edinburgh.
In the 1940s and 1950s she appeared in the films Shadow of the Past (1950), Seven Days to Noon (1950), The Lavender Hill Mob (1951), Simba (1955), Yield to the Night (1956), and The Surgeon's Knife (1957), among others. In the 1950s Ney moved into television, appearing in episodes of ITV's ITV Television Playhouse, ITV Play of the Week, and Armchair Theatre. In 1960 she appeared in the Greek film Eroica, and in an episode of Maigret. Her last credited screen appearance was in the ITV Playhouse episode Remember the Germans (1969).
- Escape (1930)
- Scrooge (1935)
- Brief Ecstasy (1937)
- Jamaica Inn (1939)
- The Romantic Age (1949)
- Conspirator (1949)
- Seven Days to Noon (1950)
- Night Was Our Friend (1951)
- The Lavender Hill Mob (1951)
- Simba (1955)
- Yield to the Night (1956)
- The Surgeon's Knife (1957)
- West 11 (1963)
- Marie Ney at the Internet Movie Database
- Ney Film Biography on Time Out
- Ney on 'Radio and TV Personalities'
- Images of Ney on Getty Images