She was born Zuzka Zenta in Vienna, Austria, the daughter of Alfred and Charlotte Burstein. When she was young, her parents moved to a ranch in central Bohemia, Czechoslovakia. Her family took her to the theater or opera in Brno, and on occasion, they would visit Zuzka's maternal grandmother in Vienna, who was the manager of the Burgtheater. She began studying ballet at the age of eight.
In 1939 her Jewish parents moved to Paris, and a year later Zuzka moved to the United States with her mother to escape the war in Europe. Emigration to the U.S. was allowed on the basis of annual quotas. Charlotte was allowed in the country on the basis of her birth in Italy, because the quota of Italy had not been filled for that year. Alfred moved to London to work for the Czechoslovak government-in-exile.
Zuzka learned English (her fourth language) by seeing three movies a day. Under the name Suzi Burstein, she attended George Washington High School in New York. After graduating in 1943, she changed her name to Susan Douglas. Her first name, Zuzka, is Czech for Susan, while she selected Douglas from a phone book.
Beginning in 1945, she began a career spanning radio, television, theater and film; she was both an actress and producer. Her 1947 movie debut was in The Private Affairs of Bel Ami. Following the film, she was offered a standard seven year contract by Albert Lewin of MGM, but turned it down to live in New York. Between 1946 and 1959, she appeared on hundreds of television shows, including both the radio and TV versions of the soap opera The Guiding Light. As her character was unmarried and she was pregnant three times during her appearance on The Guiding Light, the producer had her character sick and in an oxygen tent for the first child, and using a wheelchair for the second child, then finally had her character killed off for the third.
In 1959, she moved to Toronto, Canada and in 1963, she began introducing plays to schools. She founded the Young People's Theater in Toronto in 1965, with the goal of introducing children to the live theater experience. This was renamed the Susan Douglas Rubes Theater Center in 1977. (It later became the Lorraine Kimsa Theatre for Young People in honor of Kevin Kimsa's mother, after receiving a generous donation from Kevin.) In 1972 she served as associate editor of A Collection of Canadian plays, volume 4. She remained artistic director of the center until 1979, then moved to CBC Television. From 1982 - 86, she was the head of CBC Radio Drama. From 1987 - 89, she was president of the Family Channel.
She married the Czech-Canadian opera singer Jan Rubes on September 22, 1950, in New York City. That same year the couple appeared together in Forbidden Journey. The couple had three children: Christopher (died 1996), Jonathan, and Anthony. They remained married until his death in 2009.