Bill Daniel was the younger brother of Price Daniel (1910-1988), who was both a Governor and U.S. Senator for Texas. He studied, among others, at Baylor University. After studying law and qualifying as a lawyer, he started working in this profession for most of his life at home in Liberty County. He also served during the Second World War in the United States Army. Then he hit as a member of the Democratic Party launched a political career. Between 1949 and 1953 he was a member of the Texas House of Representatives.
Following the resignation of Joseph Flores as Governor of Guam Daniel was appointed by President John F. Kennedy to be his successor. This office he held between 20 May 1961 to his resignation on December 15, 1962, according to other sources on January 20, 1963 from. During this time he successfully lobbied for the repeal of a still derived from the 1941 restrictions on admission to Guam. Until then, any trip to the area of the United States Navy had to be approved. Daniel convinced President Kennedy to remove these once ordered by President Franklin D. Roosevelt action. That also promoted tourism.
After the end of his term as Governor William Daniel returned to Texas. There he worked as a lawyer again. He also operated a ranch. For the John Wayne Alamo movie he made 400 cattle for film shootings; He also played in the movie itself a minor role. He died on 20 June 2006 in Liberty.