Actor Joaquin Phoenix is currently turning heads with his intense performance as the Clown Prince of Crime. But as it turns out, Joker isn’t the first DC character Phoenix has played in his career. He actually made his DC debut playing Superboy on TV.
Sort of, anyway. Phoenix appeared in a 1989 episode of CBS’s Superboy series called “Little Hercules.” Credited as “Leaf Phoenix,” the actor plays a high school student named Billy Hercules (sure, why not?) who yearns to impress a girl in his class. Billy daydreams about what he’d do with Superboy’s powers, resulting in a dream sequence where Phoenix actually dons the Superboy costume and fights crime. And by crime, we mean he employs some asymmetric superhuman warfare against a trio of late ’80s TV bullies.
Source: IGN.com Before Joker, Joaquin Phoenix Played Superboy on TV