Janet Hammer spent her teen years touring as a vocalist with the Continental Singers. Soon after, she received an Associate of Arts degree in music from Palomar Community College, then a Bachelor's Degree and secondary teaching credential from San Diego State University. During this period, she sang professionally with several small groups and big bands. Just after college, she also joined the San Diego Master Chorale for eight years.
In performance, Hammer is often accompanied by pianist and arranger Nathan Fry. As of 2009, she fronts two bands, the Full Measure Carolers and the Rockin' Cranberries, in addition to working as a vocal instructor at Palomar College. She has been singing with the a cappella Renaissance group called Pacific Camerata for nearly 25 years under the direction of Dan Ratelle.