Dey was known for her roles in the family series The Partridge Family, and in the legal drama LA Law. In Germany, she received the Golden Bravo Otto in the youth magazine BRAVO because of their popularity in 1973, 1974, 1975 and 1976.
Originally Dey was intended for the casting of the female lead role in Grease ( 1978), but these refused on the advice of her manager.
From 1976 to 1981 Dey was married to Leonard Hirshan ( 1927-2014 ); from this marriage she has a daughter, Sarah Hirshan (* 1978). Since 1988 she is married to Bernard Sofronski. Susan Dey is a member of the board of the Rape Treatment Center at UCLA Medical Center, Santa Monica (Los Angeles ).