Rush was born in Seattle, Washington. As a girl, she studied the classical piano for 10 years. In 1960, Rush auditioned for a band (directed by her first husband) that played sock hops. Next, she was part of Merrilee and Her Men, doing covers of male pop hits. Then she joined a Seattle rhythm and blues group called Tiny Tony and the Statics.
The band "Merrilee Rush and the Turnabouts" was formed in 1965. One of the group's roadies worked for Paul Revere and the Raiders, which was doing a tour in the south states in 1967, and they invited Rush to be their opening act.