She was born in Maysville, Kentucky, about 60 miles up the Ohio River from Cincinnati, Ohio. Her sister, Betty, and brother, Nick, as well as her nephew, George Clooney (Nick's son), all became entertainers as well; Betty sang in a duo with Rosemary for much of her early career.
Her father was an alcoholic and she and her brother and sister were constantly moving back and forth between her parents. Eventually she and Betty went to live with their mother, Nick with their father, when Rosemary was 13. In 1945 the Clooney sisters won a spot on Cincinnati's radio station WLW as singers.
In 1951 her record of "Come On-a My House" became a hit, her first of many singles to hit the charts.
In 1968 she was present at the assassination of Robert F. Kennedy, with whom she was a close friend, and the event traumatized her life for years afterward. She had a nervous breakdown and serious drug problems.
In 1986 she sang a duet with Wild Man Fischer on "It's a Hard Business".
She had two husbands, Josť Ferrer (from 1953 until the 1960s) by whom she had five children, including Gabriel Ferrer, born 1956, who married Debby Boone, and Dante DePaolo (whom she married in 1996).