9. Jimmy Olsen - Superman
Photojournalist at The Daily Planet, friend of both Clark Kent and Superman, and briefly a superhero in his own right, Jimmy ticks all the boxes for a successful supporting character. Though traditional depictions of him range from the slapstick and slightly goofy to the more modern, serious take on him, he has always been a useful conduit figure between Clark and Superman. Jimmy first appeared in the series in the early 40s on both radio and then page, and proved popular enough to be eventually written into the series as a permanent character after a few years of dipping in and out. Instantly distinctive with his flame red hair and bow tie, his interactions in the Daily Planet office with Lois, Clark and Perry White are at turns funny and ground the more fanciful aspects of the series in a recognisable, believable atmosphere. Who doesn't love office banter? Jimmy briefly became the superhero Mr. Action in the late 2000s, who was unable to win the respect of either the JLA or the readers. In the Silver Age and during Countdown, Jimmy also underwent frequent and increasingly more bizarre transformations, a move which was a bit gimmicky and wore thin reasonably quickly. The charm of the character never did diminish though, no matter which direction it was taken in.