Alliterative Name: His first and last name don't start with the same letters, but they have the same sound.
Beware the Nice Ones: Superman always finds time to help, whether in big or small ways. He loves children, animals, and mankind in general. He's even adamant about giving someone trying to reform a second chance. However, he is extremely strong and tough and ferociously protective of the innocent. If villains mess with the people he loves, they do so at their peril.
Clothes Make the Superman: During the famous "Panic in the Sky" episode, amnesiac Clark, having discovered Superman's suit under his own, wonders if this might be the case. Unfortunately, Jimmy says no, the man makes the clothes super.
Superman Can Breathe in Space: In "Panic In The Sky", Superman not only flies through space and lands on an asteroid without trouble, but the asteroid itself apparently has birds on it.
The So-Called Coward: Lois constantly derides Clark as a coward, even though in many episodes, he acts fairly brave (notwithstanding the fact that he's really Superman), such as when he headed to Hollywood to supervise a film based on some of his articles, despite knowing he has a price on his head in the area, or when he assisted a doctor in operating on a mysterious "mole man" (who was believed to be radioactive) while outside, a mob was growing to attack the creature.
Super Hearing: In addition to his Flying Brick power set, Superman has enhanced senses, including heightened hearing that can detect trouble far away.
Unique Protagonist Asset: Superman is the only person with superpowers we ever see (and by implication the only one on the entire planet).
Intrepid Reporter: Perry at times blows his top at the trips she takes to get a story, but she tends to be following solid leads. On at least one occasion Lois was scheduled to be a key witness of a senatorial committee investigating organized crime.
Boss's Unfavorite Employee: Jimmy is the most common target of Perry's grouchiness, often for calling him "chief" (something the other reporters call him without comment). While Perry does care about him, he usually conceals it under a layer of growling criticisms.
Cannot Spit It Out: If "The Human Bomb" and "My Friend Superman" show anything, Jimmy is shy of saying romantic things.
Unluckily Lucky: Jimmy gets into trouble almost every time he appears in the show. At whatever his ambiguous age is, he's been kidnapped, knocked unconscious, pushed off a building, nearly drowned, and left in as many death traps as one could care to count. However, thanks to being friends with the world's only superhero, he always comes out fine. In fact, he doesn't even seem to have any angst from it.
Jerk with a Heart of Gold: Perry is habitually crabby and short with his writing staff (Jimmy especially, but Lois and Clark are not exempt). In "Stamp Day for Superman", he snaps at Clark that he spends half his life keeping track of them and the other half regretting it. However, he has a massive soft spot for all of them and is as protective as he can be while being a non-powered older man.
Weekend Inventor: In one episode, he discovers a way to extract uranium from seawater.