William Thomas Parsons was born in Palmerton, Pennsylvania, on January 5, 1923. He was raised by his parents, Walter Alvin Parsons (a foreman) and Florence (Greene) Parsons. After graduating high school, Parsons enlisted in the United States Army. He was a soldier from 1943-1945 and received five battle stars for his conduct in World War II. He returned home and married Phyllis J. Vibbard, a borough secretary, on December 8, 1945. Parsons then decided to attend college and received his BAin history at Ursinus College in 1947. He went on to earn his MAfrom the University of Pennsylvania in 1949.

While working on his PhD, he was a French instructor at Ursinus College until 1953. He then became an assistant professor of history and earned his PhDin 1955. As he continued to teach, Parsons became editor of the Bulletin and remained editor from 1961-1965. The year he stopped editing for the Bulletin was the same year he became an associate professor. He remained at this position until becoming a professor in 1970.

Parsons became involved in different aspects of his career while teaching. He was a member of organizations such as the American Historical Association, Pennsylvania Historical Association, and the Historical Society of Montgomery County. He's been on the board of directors for the Pennsylvania German Society since 1974 and even received a research grant from the Evangelical and Reformed Historical Society. That same year, he designed a summer senior seminar course in Pennsylvania Dutch Ethnic Studies at Ursinus College. One year later, Parsons became assistant editor for Pennsylvania Folklife and after proving himself in this field, he decided to take a stab at writing historical novels, particularly about the Pennsylvania Dutch.

In 1976, The Pennsylvania Dutch: A Persistent Minority was published. In this work, Parsons focused on the Pennsylvania Dutch descending from German heritage, not Dutch. He emphasizes their descent from early German-speaking settlers who arrived in Pennsylvania prior to the Revolutionary War and the War of 1812. Along with focusing on their religion and political history, Parsons reflects on the Pennsylvania Dutch of today and how 300,000 people speak the Pennsylvania German dialect today and 400,000 more understand it, mostly in Pennsylvania. Parsons also enjoyed learning about and working on other topics. In 1986, he edited Arms Control and Strategic Stability: Challenges for the Future. This work contained sixteen short essays on arms control, which were presented at a conference at the University of Virginia. The essays gave a background in arms control practice and provided perspectives on implications of control, topics which are very much mainstream today.

In 1988, as his health was deteriorating, Parsons returned to editing and contributed to The Outhouse Revisited. This comical work presented 50 pictures of outhouses and shared stories about Sherman Hines' collection. Unfortunately, Parsons' health could not hold up as well as his contributions to the literary world, and he died in 1991. He is survived by his students' memories, his editorial skills, his literary works, and the creation of the Ursinus College Parsons Prize in History.