Born Sarah Tilghman in Baltimore, Maryland she was the daugher of James and Elizabeth Haughton Tilghman. She attended Goucher College in Baltimore. After graduation she taught science at Winston Salem Academy in North Carolina for several years. Sarah then returned to school to the study of law. In 1919 she moved to Washington, D.C and attended law school at George Washington University. She attended classes at night and during the day worked as a police officer. At that time she lived in a tent home near the Potomac River and commuted to the campus by canoe each evening.
She moved to Dallas, Texas in 1922 with her husband, George Hughes, whom she had met in law school. She practiced law for eight years in Dallas before becoming involved in politics, first being elected in 1930 to three terms in the Texas House of Representatives. In 1935 she accepted an appointment as a state judge from Governor James Allred for the the Fourteenth District Court in Dallas and was the state's first woman district judge. In 1936 she was elected to the same post. She was re-elected six more times and remained at that post until 1960.
As a reward for her involvement with the Democratic Party in 1961 President John F. Kennedy appointed her to the federal bench. She was the first woman to serve as a federal district judge in Texas. Two years on later on November 22, 1963 she was called upon to administer the oath of office of Lyndon B. Johnson. She was the a member of the three judge panel that overturned the decision in the Roe v. Wade which was subsequently upheld by the United States Supreme Court. She retired from the active federal bench in 1975 though she continued to work as a judge with senior status until 1982.