A super-hero who first appeared in Action Comics #1 in June 1938. The adventures of Mr. America are published by DC Comics.

Harold Thompson was your ordinary, run-of-the-mill business man until he struck it rich in the oil fields of Texas. Besides making him rich beyond the dreams of avarice, this episode in his life also earned him the nickname "Tex". Thompson used his newfound wealth to travel the country. While touring the United States, he pursued his love of detective work, solving crimes he came across. He was helped in these adventures by his friend Bob Daley. Thompson and Daley even became special agents for the district attorney in one city.

Thompson resigned his position to work with relief workers, aiding the victims of the fighting during World War II. While traveling on the ship Angelus to Europe, Thompson and the rest of the crew were betrayed by a Nazi spy and the ship was sunk. Thompson was washed up on the shores of Portugal and vowed to track down spies and others who would betray the American way.

Thompson returned to the United States in the guise of Mr. America. Dressed in red, white, and blue and wearing a domino mask, Thompson began his crusade against the hidden menace. He would whistle Yankee Doodle to freak out his enemies and fought his battles using a whip. He also had a cape that allowed him to fly when he stood on it, but how this occurred was never explained. He tracked down the spy who had betrayed the Angelus and brought him to his own style of patriotic justice.

Mr. America eventually teamed back up with his friend and former partner Bob Daley. Realizing that Bob Daley was a silly name for a super-hero, Daley came up with the identity of Fatman which got him off the hook for having to go to the gym with the rest of the mystery men.

Eventually, Mr. America was recruited by FDR to become a new and better hero called the Americommando. He underwent intensive training and fought in both the European and Pacific theaters of World War II. The Golden Age mini-series tells of how Thompson was hailed as a hero upon his return to the U.S. and elected to Congress.