Growing up in Manhattan, Manchester became a student of the arts at the urging of her father, who played bassoon with Metropolitan Opera. As a teenager, she attended the New York High School for the Performing Arts (immortalized in the musical, Fame), while moonlighting as a session vocalist on advertising jingles.
Soon after, she was signed as a songwriter by Chappell Music, and while attending NYU, she enrolled in a songwriting class taught by folk-rock icon Paul Simon. The songwriting class taught by Simon inspired her enough to begin performing her own material on the thriving New York club circuit.
One night while performing at the Bitter End, she was discovered by an up-and-coming singer named Bette Midler, and her musical director, pianist Barry Manilow. The two hired Manchester as a back-up vocalist in 1971, and soon after, Manilow brought her to the label where he had his own deal, Bell, later renamed Arista Records.
Arista signed her, and in 1973 her first LP, Home To Myself, was released, featuring mostly original material she had co-written with another aspiring writer, Carole Bayer-Sager (Bayer-Sager would become a pop composer superstar in her own right, and eventually, Mrs. Burt Bacharach).
She would score Top 10 hits with a number of pop ballads that included "Midnight Blue," "You Should Hear How She Talks About You," (which won her a Grammy), "Come In From The Rain," and "Don't Cry Out Loud," (written by the late Peter Allen.
By the late 1980s, Manchester's recording career had faded and she focused more on acting, including a role in the Bette Midler epic, For The Boys. She returned to touring and recording in the 1990s, and released her last album on Koch in 2004.