Jensen Ackles

  played Jason Teague [Season 4] in Smallville

Jason comes to Smallville to be with Lana and go to college. He takes the job as the assistant football coach at the highschool. At the end of the 4th season Jason was killed in the meteor storm.
played Dean Winchester in Supernatural

When Dean was only 4 years old, he witnessed the supernatural death of his mother. As she burst into flames, his father told Dean to take baby Sam and get out of the house. Ever since then, Dean, like his father, has been devoted to finding the cause of his mother's death, and destroying other demons along the way.

Dean grew up along side his father, learning how to track and hunt demons. When his father dissappeared during a hunting trip, Dean went to Sam to convince him to help him find their father. Once Sam agreed to go, they've devoted their lives to finding their father and seeking revenge on the demon that killed their father.