Older Than Feudalism: Creon from Antigone has been interpreted as an extremist, although to the audience of the day his actions were seen as less extreme, and Antigone's as more controversial, than to most audiences today. He insists on law and order at the expense of basic compassion, enforcing his often baffling edicts with the death penalty. But while he's one of the archetypal dictators of literature, he sincerely wishes peace and prosperity for his country. He's also seen as something of a family man, bending over backwards to offer his prospective daughter-in-law forgiveness of her rebellion, should she accept it.
Brutus from The Fall Of Julius Caesar legitimately believed that killing off Caesar would be for the best of the Roman Republic. In fact, he was actually reluctant to do it unless there were people besides senators who wanted it done. Unfortunately, he had to do this as well as go to war with what was once his home with the rest of the conspirators.
Giovanni da Procida from Verdi's opera I Vespri Siciliani (The Sicilian Vespers). He'll sacrifice anything for the freedom of Sicily (he says so himself), and his actions eventually lead to a Kill 'em All ending.
The Wizard of Wicked. He was, in his words, practically thrust into being leader of Oz during an age of strife, and people wanted someone or something to blame. He cynically gave them one. He genuinely believes Oz will fall apart without a common enemy to unite against: he simply used the animals as a scapegoat, but wants to care for his city - and, especially, the students who come to see him.
Ned Weeks in The Normal Heart comes off that way whenever he is getting interviewed on TV.
Jason "J.D." Dean from Heathers only wants to make the world a decent place for people who are decent. He decides to achieve this by murdering anyone he doesn't think is decent. Which in his mind, by the end of the show, means everyone at Westerberg High except for himself and Veronica. It's only due to Veronica's interference that he doesn't succeed in planting a bomb and blowing up the school. And at the end of the show, he takes said bomb from Veronica (who had intended to make a Heroic Sacrifice to save everyone else), and blows himself up because he's "far too damaged, but you're not beyond repair."