Shirley Baumgardner earned the baccalaureate degree in political science and economics from UT in 1943 and the bachelor of law degree in 1948. As an undergraduate, she was a member of Alpha Delta Pi sorority and served on the staff of Carnicus and the Volunteer. As a law student, she was a member of the UT Bar Association and the Usher Corps. Following graduation from Law School, she practiced in her native Bristol with her father, John Dixon Baumgardner. In 1956 she married Dr. Charles T. R. Underwood, a prominent physician and surgeon. In 1961 she was appointed juvenile court judge of Johnson City by Governor Buford Ellington, was elected to a full eight-year term in 1962, and was subsequently reelected four times. At the time of her retirement in 2002, she was the longest sitting juvenile judge in the nation.
She served as president of both the Tennessee Council of Juvenile and Family Court Judges and the Southern Institute of Juvenile Court Judges and served two terms on the Executive Committee of the National Council of Juvenile and Family Court Judges. In 1995 the National Council of Juvenile and Family Court Judges bestowed upon her its highest honor, naming her America’s Outstanding Juvenile and Family Court Judge. In 2001 she was among those honored in “50 Years of Pioneers: Early Women in the Law” by the Lawyers Association for Women. Judge Underwood was the first woman to be elected by UT alumni of the First Congressional District to serve as their representative on the UT Board of Governors (1970–73). She was honored as a Distinguished Alumna of the College of Law in 1984 and received its Alumni Leadership Award in 1989. The Judge Shirley Baumgardner Underwood Classroom at the College of Law was dedicated in October 2002, the same year she received the UT Notable Woman Award.