The history of the criminal known as the Key is largely unknown. He first came to public attention in the Spring of 1951 when the Justice Society hosted a charity event in which four internationally famous detective attempted to solve a test crime designed by the Justice Society on stage in a large auditorium.  In a recreated transparent department store of a famous jeweler, the four worked until a sudden dousing of the lights blinded the audience.  Once light was restored, the four detectives were gone.  While the JSA scratched their heads, telegrams arrived requesting each of the four detectives to return him and handle a major crime.  With the sleuths gone, the JSA split up to solve the crimes for them and attempt to find clues of their disappearance.

Each case was tackled around the world by different JSA members.  A major bank robbery case in England was solved by Dr. Mid-Nite while the Flash resolved the thefts of the gargoyles of Notre Dame in Paris.  In Turkey, Wonder Woman capture thieves after the Emir's gold and in Hawaii, Green Lantern lures out a thief after a $100,000 collector's item.  In each case, the criminals involved mentioned "The Key"  but no one knew who he was. 

Returning to Civic City, the JSAers found the Black Canary standing guard in the empty auditorium.  There she shared that the Atom and Hawkman had pursued clues in Civic City to find the missing detectives.  They find the Key's mens but the Key himself eluded them.  Giving chase, the trail led to Secaucus, NY north of Civic City.   There they find the detectives hypnotized.  As they searched for the mastermind behind all this, a screen appeared and one of the detectives - Inspector Drew Dawes - spoke to them.  As the JSA stared, Dawes removed his face and an unknown man announced himself as the Key.  He had captured the real Dawes at the outset and impersonated him at the auditorium, allowing the capture of the other men.

As the JSA thwart the hypnotized detectives, the Key flees in a cable car over a ravine near his hideout.  Wonder Woman repels his shots fired in his escape and the Atom uses his super strength to begin to reel the car back in.  Realizing his was captured, the Key leaped to his supposed death (All-Star Comics #57).

Whether he was truly killed is unclear.  Several reports including the original document the Key in an unusual lock-shaped mask in direct conflict with the JSA, suggesting he had lived and other cases (Adventure Comics #466, America vs. the Justice Society #4).  Whether these cases were actual, rather than apocryphal and undocumented cases of the Key exist remains unknown.