She sang regularly in school, starting at age seven in a church choir, and at 17 decided to become a professional singer. After meeting Warne Marsh the following year, Niemack became dedicated to jazz. She attended Pasadena City College, had several years of classical study, and also attended the New England Conservatory in Boston and the Cleveland Institute of Music, in addition to private lessons with Marsh. In 1977, she moved to New York and the following year made her recording debut for Sea Breeze.

Since that time, Niemack has freelanced with many top advanced musicians, including Toots Thielemans, James Moody, Lee Konitz, Clark Terry, Kenny Barron, Fred Hersch, Kenny Werner, Joe Lovano, and Eddie Gomez, among others, written lyrics to other musicians' compositions (in addition to writing songs of her own), and has toured Europe regularly. In addition, she has been a top jazz educator, teaching throughout Europe. Judy Niemack, a colorful improviser, has recorded as a leader for Sea Breeze, Stash, and Freelance. ~ Scott Yanow