[1] She is remembered for her starring roles in the British classic films The Dark Eyes of London, Mr. Emmanuel, Take My Life, Dear Murderer and The Ringer.

Her most famous films are the 1939 Bela Lugosi film The Dark Eyes of London as the tough heroine, heroic as an underground leader in Tomorrow We Live (1943), touching as Jewish Elsie Silver in Mr. Emmanuel (1944), forceful as loyal wife proving her husband's innocence in the thriller Take My Life, a promiscuous murderess in Dear Murderer, both in 1947, and as a nightclub singer singing "The Shady Lady Spiv" in Easy Money (1948).

After the Swedish film The Song to Her (1934), her mother, costume designer Kirsten Woxholt, felt Gynt would have better luck in Britain.

She continued with leading roles in The Common Touch (1941); Tomorrow We Live (1943); It's That Man Again (1944) with Tommy Handley; and Mr. Emmanuel (1944) with Felix Aylmer.

[10][11] She played a glamorous Saxon aristocrat in the 1956 episode "The Friar's Pilgrimage" of the British TV series The Adventures of Robin Hood.