Baker was born to a
Jewish family in
Brookline, Massachusetts, on September 4, 1923, daughter of Attorney Mark Shain and Professor Rose Wies Shain, she grew up next door to Joseph and Rose Kennedy and their children, including John F. Kennedy. Baker began her music career as part of a singing trio, The Shain Sisters, alongside her older sisters, Esther and Thelma. Baker also arranged music for composers such as
Stephen Sondheim and
Irving Berlin. Shayne met her first husband,
French born
Noël Regney, while playing
piano at a New York City hotel in 1951. Regney and Shayne would later write "Do You Hear What I Hear?" together as collaborators. They were married the same year that they met. The couple divorced in 1973. Regney died in 2002. Shayne married her second husband, William Baker, in 1973. He died in 2001. ==Songwriting==