After her studies at the Berklee College of Music in Boston, 35 years old Tierney became a semi-finalist in the Thelonious Monk Jazz Vocal Competition in 1998. The year after this recording was originally released, being her CD debut as a soloist. It received rave reviews and was nominated for a 1999 Indie Award for Best Jazz Vocal Album. "A serious jazz artist who takes the whole enterprise to another level" stated The New York Times.
Later that year, Tierney signed with the Telarc Jazz label and released five more albums, all with the same group of msicians, demonstrating what collective consultation and dedicated teamwork can achieve. She debuted at Carnegie Hall in February 2005 and later that year her album "I'm with the Band" was nominated for a Grammy Award in the category of Best Jazz Vocal Album. Tierney's voice was recently featured on "The Cooler", a movie starring William H. Macy and Alec Baldwin and in "Twisted", starring Samuel L. Jackson , Andy Garcia and Ashley Judd. In 2004, Tierney and her band scored the independent feature film "Blue in Green". Her voice is also regularly featured in commercials for e.g. BMW and Coca Cola.