Martian Manhunter
Played by: Phil Morris
Appearances: 13 episodes (S6/7/8/9/10)
Intergalactic bounty hunter J’onn J’onzz used to be an ally of Jor-El and later aided his son Kal-El and the Justice League. For a period he lost his powers, causing him to live on Earth as Metropolis detective John Jones. Though the Martin Manhunter’s true form was only briefly glimpsed on the show, his fashion sense alluded to his usual comic book costume.
Supergirl
Played by: Laura Vandervoort
Appearances: 17 episodes (S7/8/10)
Clark’s Kryptonian cousin Kara-Zor-El was sent to Earth to protect him – but crashed into Smallville’s Reeve’s dam and was not awakened until Clark was fully-grown. The pair were then able to guide each other: Kara helped Clark learn about his origins and the extent of his powers and he aided Kara in adjusting to life on Earth.
Green Arrow
Played by: Justin Hartley
Appearances: 56 episodes (S6/7/8/9/10)
In Smallville, Clark’s best super-friend isn’t Batman, it’s Green Arrow. Though Clark Kent and Oliver Queen have conflicting personalities, and differ on their crime-fighting methods, the pair grow to become as close as brothers across the series. Uniquely, Smallville‘s Oliver Queen is the founder of the Justice League, though Clark later assumes command of the team.
Superman
Played by: Tom Welling
Appearances: 215 (S1-10)
Smallville obviously took a lot of liberties with the character of Clark Kent – his inability to fly during his youth, his teenage friendships with Lex Luthor and Lois Lane ETC. But at the core, Tom Welling’s Clark Kent was everything Superman always is. A humble man with the powers of a god who inspires hope in those he meets and rises to become Earth’s greatest saviour.