The Jester is Charles Lane, a Golden Age vigilante super-hero who was active during World War II. He began his career as a cop, then decided to fight crime wearing a costume after he learned he was descended from a line of medieval jesters. He has been a member of the Freedom Fighters and the All-Star Squadron. His grandson Charles Lane II is his successor in the modern era. The Jester was created by Paul Gustavson, first appearing in the Quality Comics publication Smash Comics #22. (1941)
Quality Comics also published another character with the name "Jester" several months earlier, Robert Mason, but he did not achieve the same popularity.