In 1976 Cowsill signed with Warner Bros. Records and released two singles. She worked as a backing vocalist for artists such as The Smithereens and Hootie & the Blowfish. She joined the Continental Drifters and occasionally appeared in the duo The Psycho Sisters. Her debut solo studio album Just Believe It was released in 2005. Her second album Lighthouse was released in 2010 and The Psycho Sisters debut album Up on the Chair, Beatrice was released in 2014.