While at the university he was one of the early members of Florida Blue Key, as well as the Tau chapter of Theta Chi fraternity.

Warren was nominated for governor by the Democratic Party in 1948; his platform included promises to fight racism in Florida.

After his election, he spoke out against the Ku Klux Klan, stating after a rally in January 1949 that The hooded hoodlums and sheeted jerks who paraded the streets of Tallahassee last night made a disgusting and alarming spectacle.

In 1951 Warren signed an anti-Klan law which, although not mentioning the Klan specifically, forbade the wearing of masks in public or on the private property of another person without the written permission of the owner.

"[11] He ran for governor again in 1956, promising "to maintain segregation in Florida"[12] but lost the election to opponent LeRoy Collins.