William Prentice Cooper Jr. (September 28, 1895 – May 18, 1969) was an American politician and diplomat who served as the 39th governor of Tennessee from 1939 to 1945.

[2] In 1914, Cooper enrolled in Vanderbilt University, where he was a member of Phi Delta Theta and vice president of the freshman class.

[2] Following the U.S. entry into World War I, he enlisted in the Army, initially serving with the 307th Field Artillery before being transferred to Fort Monroe in Virginia.

That same year he was elected to the Tennessee House of Representatives, where he secured passage of the state's Uniform Declaratory Judgments Act.

[4] In the 1942 race, Judge J. Ridley Mitchell, who despised Crump, sought the party's nomination for governor but was defeated by Cooper, 171,259 votes to 124,037.

[1] In 1942, the federal government appropriated land in what is now Oak Ridge, Tennessee, for the top secret Manhattan Project which was developing the world's first atomic bomb.

When officially notified in July 1943 by an Army lieutenant of the presidential proclamation making the area a military district not subject to state control, he angrily ripped it to pieces.

[6][7] Along with defense mobilization, Cooper increased funding for state schools and implemented a program that provided free textbooks for children in grades 1 through 3.

[2][dead link‍] Cooper was among 12 nominated at the 1944 Democratic National Convention to serve as Franklin D. Roosevelt's running mate in the presidential election that year, receiving 26 votes.

He convinced Peru to repay an outstanding loan to the United States and had a reputation as a frugal entertainer.

Cooper remained an active participant in Democratic Party events until his death from cancer on May 18, 1969, at the Mayo Clinic in Rochester, Minnesota.