William was born in Scotland and earned a M.A. degree from the University of Edinburgh in Scotland. He migrated to Boston, Massachusetts in 1737, and was ordained and became the first pastor of West Congregational Church in Boston. William married Mary Dennie on October 18, 1739 [Recorded from Commissioners Report Boston Marriages 1700-1751. Gen 974.4 B747 (Mass.)]. After nine years of pastoral service at West Church, William chose to be part of the Episcopal Congregation and was summoned to England to be ordained by the Bishop of Gloucester into the Church of England (Episcopal Church in the colonies). On his return to Boston, William was called as rector (pastor) of Trinity Church in Boston in 1747. Rev. Hooper served as rector at Trinity for twenty years. He served until his death in 1767. William died while walking in his garden on the evening of April 14, 1767. He was well loved and remembered for years by the Trinity congregation after his death. He and Mary had five children; William, George, John, Mary, and Thomas. Although he wanted his oldest son William to be a minister as well, he studied law under James Otis and became a member of Congress from North Carolina in 1776 and eventually a signer of the Declaration of Independence.