She began acting in England, with some minor TV roles. Then, in 1953, she relocated to France and while occasionally working as a governess also sang and danced in nightclubs, where she met Director Marcel Camus. At the age of 24 she won the role of "Eurydice" in his film Black Orpheus. The film won the Palme d'Or at the 1959 Cannes Film Festival and the 1960 Academy Award for Best Foreign Language Film. She married Camus, but divorced him soon after and married Belgian actor Eric Vander. Considered a great beauty, she was featured in November 1959 by Ebony and has been hailed as "one of Ebony magazine's prettiest cover girls, along with the likes of Dorothy Dandridge, Halle Berry, Vanessa Williams and Lena Horne".

Dawn remained in Europe, working without in French films and television. She also had several theatrical parts, including a starring role in Chérie Noire, a highly successful stage comedy which played for seven years, touring France, Belgium, Switzerland, Tunisia, Algeria and Morocco, and Le Jardin des délices (The Garden of Delights), by Fernando Arrabal, with Delphine Seyrig, 1969. Her subsequent career, however, was much less successful. She appeared in a 2005 documentary about Vinicius de Moraes, who wrote the original play from which Black Orpheus was adapted. She and her fellow lead from that film, Brazilian actor Breno Mello, died just 42 days apart in 2008, both from heart attacks. She was 74 years old and at the time of her death in Paris and left five children and four grandchildren.