B-movie bad girl Fay Spain was born in Phoenix, Arizona, on October 6, 1932 (some sources cite 1933 as her year of birth). Her childhood proved to be so tumultuous that she left home at the age of 15 and supported herself working odd jobs. Her acting career began in New York, where she did summer stock work. A few stage roles ensued, followed by some television work. While still a teenager, she married actor John Falvo. The short-lived union produced a son and quickly ended in divorce. With a son to support, Spain tried hard to build a modeling and acting career. Perhaps her earliest TV appearance was as a contestant on the TV game show You Bet Your Life hosted by Groucho Marx. By 1956, Spain was having success landing roles on several popular TV series of the day, including Lux Video Theatre and Cheyenne with Clint Walker. The beautiful Spain was also a popular pin-up of the day, often appearing in magazines of the era.

In 1957, Spain made her film bow in the juvenile-deliquent cult film Dragstrip Girl with John Ashley. Other films followed, including Teenage Doll (1957; with Ziva Rodann and Barboura Morris), God's Little Acre (1958; with Tina Louise), and The Beat Generation (1959; with Steve Cochran and Mamie Van Doren. While Spain's film career was rather short, she seemingly preferred taking roles on television, where her work was prolific in the 1960s and 1970s.

After appearing in the sword and sandal epic Hercules and the Captive Women (1961; with Reg Park), Fay Spain's film appearances became sporadic. In 1962, she divorced her second husband, John Altoon, an artist. She remarried again in 1965 and was divorced the following year. In 1968, she married fourth husband Philip Westbrook. Spain continued to work in films and on television until the mid 1970s; her last film appearance was in The Godfather, Part II (1974; with Al Pacino). Afterward, she retired from acting to care for her husband, who was ill. Sadly, Fay Spain died of cancer on May 8, 1983, at the age of 50. She was survived by a son and her fourth husband.