His works focused on the historical research of nontrinitarian Christian movements that emerged during the Protestant Reformation, primarily Socinianism and Unitarianism.
[1] His father David Rhys Williams was a Unitarian minister who signed the Humanist Manifesto,[2] while his grandparents were Congregationalists.
Williams changed his middle name as a young man and chose the name of his village, Huntsburg, Ohio.
After his academic studies in history of Christianity at the European universities of Paris and Strasbourg, he returned to the United States and became assistant minister of a Unitarian church in Rockford, Illinois, where he married his wife Marjorie Derr in 1941.
In 1962 he was one of several official Protestant observers who attended the sessions of the Second Vatican Council,[1] where he met the future Pope John Paul II.