Dolores Casey was born Margaret Dolores Katherine Casey in Brooklyn, New York. She was educated at Sacred Heart Academy. Then she studied journalism at Columbia University and started modeling. A talent scout spotted her and signed the nineteen year old to a contract at United Artists Studio. She spent a year at the studio but never made a single film. In 1933 producer Samuel Goldwyn hired her to be one of his "Goldwyn Girls" dancers. Dolores made her film debut in the musical Roman Scandals with Lucille Ball. Soon after she signed a lucrative contract at Paramount. The dark haired beauty had small parts in the films Dames, Big Brown Eyes, and The Case Against Mrs. Ames.

She developed a severe case of tuberculosis in 1936 and was hospitalized for several months. Her Hollywood friend, including William Frawley and director Ray McCarey, helped pay for her medical bills. Dolores returned to acting in 1938 with a role in Doctor Rhythym. She dated Arthur Tracy and was briefly engaged to director Bob Linden. Sadly her tuberculosis returned and she was forced to quit making movies. Her final film was the 1939 drama King Of Chinatown. On July 5, 1943 she married Lee Wynne, a doctor. The couple lived a quiet life in Los Angeles but her health quickly deteriorated. Tragically on May 11, 1945 she died from tuberculosis. Dolores was only thirty-two years old. She was buried at Gate of Heaven Cemetery in Hawthorne, New York.