Okay, now that I've driven away half my reader base, never to return...and half the rest are laughing hysterically at my social blunder and obvious lack of intelligence...allow me to illuminate.
Professional wrestling is a television show pretending to be sports; think "soap opera for guys." Wrestlers are actors and stuntmen, putting on a match where they try to appear to be beating the snot out of each other--hopefully, without actually beating the snot out of each other, because there's always another show to do the next night. The wrestlers know who is supposed to "win" the match, but the actual wrestling is basically made up on the spot between the wrestlers.
Most wrestling plotlines involve the "Face" (good guy) opposing the "Heel" (bad guy). Faces wrestle by the rules, while heels cheat. More importantly, faces try to get the crowd to cheer for them, while heels try to get them to boo. They can do this in the ring, or on the microphone:
"It's so nice to be back in Canada. I've been walking around, smelling the fresh
air, saying hello to all the Torontonians. I'm so glad I left. This place
sucks!" --Chris Jericho
In the wrestling world, faces become heels, and vice-versa. If the hero has gotten stale, and isn't getting cheers anymore, well, he can have a scripted "change of heart." He might start berating the crowd for not cheering him, and start beating up on his friends and other good guys; bingo, instant heel. Or the heel can be pushed over the edge, and "rescue the damsel in distress," and change back into a hero again.
That's the point of this essay. There has to be a key moment where the good guy becomes a good guy...an action that defines the character completely. An action that lets the viewer forget all of the past history of that character, and start a whole new chapter in their life...or, at least, in their wrestling career.
Two wrestlers fight a "best of seven" series. They are matched perfectly, tied 3-3 going into the seventh match. One of the wrestlers gets knocked out of the ring, and while he's getting up, and dusting himself off, another wrestler sneaks into the ring and whacks his opponent with a steel chair. The first wrestler sees this...and defines himself as "totally honorable good guy" by refusing to win the match by cheating. Or defines himself as totally unscrupulous and opportunistic by getting the win and celebrating how much he "did it by himself."
Characters need defining moments. Every character has one instance in their life that defines who and what they are--an event that lays the foundation for everything they do after that. Maybe your character is trying to make amends for his heinous and evil act years ago. Or maybe that character has never had that defining moment, and the story is about how they handle it when it arrives.
Regardless, that shining (or badly tarnished?) moment in the character's life reflects in everything they do from that point on, and defining that moment will go a long way towards defining the character in your story--whether they're smooth talking Canadians or gravel-voiced professional wrestlers.