Rosemary Butler began her career playing bass and singing in an all-girl band named the Ladybirds. The band appeared on several LA area television shows before opening for the Rolling Stones in 1964. She then joined all-female hard rock band Birtha who released two albums for Dunhill Records. After they split in 1973 she became a popular back-up singer in the late 1970s and early '80s. Her vocals were featured on Bonnie Raitt's album, Sweet Forgiveness, on songs "Gamblin' Man", "Runaway", "Sweet Forgiveness", and "Two Lives."
Butler has worked extensively as a back-up singer for Linda Ronstadt, James Taylor, Warren Zevon, Neil Young, Bonnie Raitt, Jackson Browne, and Rosanne Cash among others. She released a solo album, Rose, in 1983.
She sang in Japanese motion picture soundtrack Dirty Hero (汚れた英雄), its title track "Riding High" in 1982. She was also Co-Contractor of the 100 voice choir on Neil Young's album Living With War. She has vocal coached numerous famous voices. She cofounded "The National In Choir," an LA-based volunteer holiday choir with singer/lyricist Deborah Pearl.