Jack Kennedy

In 1939 (Superman no. 1, Summer 1939) Clark Kent overheard word of a mob attacking the county jail, after applying for a job at the Daily Star. As Superman, he stopped the mob and began questioning the prisoner, who insisted:

"I'm being held for the murder of Jack Kennedy. But I didn't do it... and neither did Evelyn Curry, the girl who's being electrocuted tonight for it!"

Learning that someone named Bea Carrol was responsible for the crime, Superman forcibly took her to the governor's mansion. After being denied entrance, Superman smashed down the door, entered the governor's room through another steel door, and stopped Evelyn Curry's execution, with the real murderer's confession in hand. Thus, the true murderer of Jack Kennedy was revealed and the innocent suspects released.

24 years later, after the real Jack Kennedy was assassinated, DC Comics published "Superman's Mission for President Kennedy" (Superman No. 170, 1964) at the request of President Lyndon Johnson and the Kennedy family. In the story, originally pulled from publication, Superman flew about convincing children to exercise, in support of the President's fitness program.