Glenn Herbert McCarthy (December 25, 1907 - December 26, 1988) was a wildcatter and a charismatic oil tycoon. The media often referred to him as "Diamond Glenn" and "The King of the Wildcatters". McCarthy was an oil prospector and entrepreneur who owned many businesses in various sectors of the economy. McCarthy founded the Shamrock Hotel in Houston, which gained him national fame and inspired the fictional character Jett Rink in Edna Ferber's 1952 novel Giant along with its 1956 film adaptation, which starred James Dean in the role.