Born Alexandra Zuck to John and Mary Zuck, in Bayonne, New Jersey, Dee, of Rusyn ancestry, was a professional model by the age of four. She progressed to television commercials and then made her first film, Until They Sail, in 1957.

In 1958 she won a Golden Globe Award for "Most Promising Newcomer" (along with Carolyn Jones and Diane Varsi). Her film career flourished, and she became known for her wholesome ingenue roles in such films as Imitation of Life, Gidget and A Summer Place (all in 1959).

Her marriage in 1960 to singer and actor Bobby Darin at the age of 16 (or 18) kept her in the public eye for much of the decade. She was contracted to Universal Studios, who tried to develop Dee as a mature actress, and the films she made as an adult--including a few with Darin--were moderately successful. They had one son together, who took the name Dodd Mitchell Darin, but in 1967 she and Darin were divorced.

During the 1970s she took very few acting roles, but made occasional television appearances. Her 1950s persona was the inspiration for the song "Look At Me, I'm Sandra Dee," featured in the 1972 Broadway musical Grease. The song later reappeared in the 1978 film version of the play, which starred John Travolta, Olivia Newton-John, Stockard Channing, Eve Arden, and Sid Caesar.

Dee's adult years were marked by ill health. She admitted that for most of her life she battled anorexia nervosa, depression and alcoholism. In 2000, she reported that she had been diagnosed with throat cancer and renal disease, but it seems that the throat scare was unfounded. Complications from the kidney failure (aka End Stage Renal Disease-ESRD), combined with a bout of pneumonia, led to her death on February 20, 2005, in Thousand Oaks, California.

Depending on sources, she was either 60 or 62 at the time of her death. It had been widely reported that she was 62, but this may have been due to her mother's policy of misrepresenting Sandra as two years older to accelerate her career. Because of this, many sources listed her birth year as 1942. Adding to the confusion, it was reported that her son, Dodd Darin, said she was 63 at her death ]. The final New York Times Sunday Magazine for 2005, in its necrology, stated that Dee was 60 at the time of her death, not 62, and factored in the two-year misrepresentation, lending credence to the 1944 birth year.

At the time of her death, she was survived by her son with Bobby Darin--Dodd Darin--and two granddaughters Alexa and Olivia.

Her life with Bobby Darin has been dramatized in the 2004 film Beyond the Sea, in which she was played by Kate Bosworth.

It is noteworthy that at the peak of Sandra's fame, while mainstream Hollywood turned its focus, lensing and marketing mature female roles and their inherent sexiness, Dee's demure role as "Gidget" became arguably (even though there were other child stars in the studio stables at the time), the epitome of the Teen Screen Queen, which then went a long way to solidify the '50's - '60's American teen male ideal of falling in love with the "girl next door".