Reggie Dunlop, in Slap Shot (W).
Yeah, we all throw accolades at Paul Newman for the humanity he brought to The Hustler, Hud and Cool Hand Luke. He deserves them. And while I have not seen every film Newman made, I doubt he ever played a more reprehensible character than Reggie Dunlop.
The movie's script, storyline and pacing are a complete hash -- the sort of scrambled-eggs-for-the-hangover project that would never get green lighted by today's studios, but was the standard for the 70s. Slap Shot is a choppy exercise at best, but oy! does it ever stick to the brain cells. It's lewd, crude, degenerate, unreflective and unrepentant, and at the center is Newman's Dunlop, who embodies all these traits to perfection. One gander at that picture reveals exactly what Newman brought to the set: a man whose body was too old to play decent hockey and whose personality was too locked-in by Type-A (for "Adolescent") cunning to be decent about anything.
Reggie Dunlop is an awful man (language warning!). And the fact that I didn't want to miss a single second of Newman's performance in this film is a tribute to his remarkable capacities as an actor.