Jason David Frank, who played Tommy Oliver in the series, started off in the series as the evil Green Ranger, but was turned good after the first few episodes. He then lost his power and came back as the White Ranger and took over the leadership of the group. His role then changed themes several times, not only becoming the Red Zeo and Turbo Rangers, but eventually the Black Dino Thunder Ranger as well.
Currently, Frank is a MMA fighter, and while he hasn't competed in too many official bouts yet, he has made an impressive mark in the arena so far. As it turns out, he is also a major fan of skydiving and claims to have over 600 dives under his (black) belt. At the Wizard World New Orleans Q&A session, he was asked a variety of questions about all of these aspects of his life.
Of course, the main focus of the questions surrounded his time as an actor for the Power Rangers. One question asked why he returned in 2002 for the Dino Thunder series. He thought it would be good to go back and return to that character and he's always wanted to be a doctor. He says he can now respond when someone is looking for a doctor "I'm not one, but I played one on TV." He just hopes when he gets the chance, it isn't a situation where someone is seriously injured.