Unscrupulous Hero

Not all fictional heroes are the sort of person you might expect to be a hero of a story. The idea that there is an "Ideal Hero" and there are "antiheroes" who deviate from the ideal has been around since classical antiquity if not earlier. Since then, writers have explored many types of antiheroes, each of which lack one or more traits of an Ideal Hero.

An Unscrupulous Hero is an Anti-Hero or Anti-Villain who lacks the moral character of an Ideal Hero, but is A Lighter Shade of Gray than the antagonists.

This lack of morality is defined by the following characteristics:

It isn't simply a case of being aloof, a screw - up, or having bad habits. Their bad behavior clearly goes into territory normally reserved for villains.
Unlike a Combat Pragmatist or Good Is Not Nice character, these characters don't just do what they have to to survive and take down the Big Bad. Their misdeeds are often done for purely selfish reasons, with little reservation, or even just for fun.
Unlike a Heel Face Revolving Door or Wild Card, rather than switching sides between heroic and villainous phases, they remain on the heroes' side without giving up any of their villainous characteristics.

Despite this, these heroes share one overriding heroic trait: unlike a Nominal Hero, they are heroes in the true sense of the word: when they have to take a stand on one side or another, they choose to fight for good for a morally positive reason, and aren't just helping the heroes for selfish reasons.

In terms of sympathy, personality, etc., these characters can vary widely. For some, their admirable motivation may be the only thing keeping them out of Complete Monster territory; others may be highly sympathetic, having all the characteristics of a likeable Anti-Villain combined with the fact that they are willing to sacrifice for a good cause.

Compare with Sociopathic Hero, Nominal Hero, heroic Tricksters and Token Evil Teammate for other morally ambiguous "heroes". Contrast with the Well-Intentioned Extremist, Knight Templar, Tautological Templar and Visionary Villain for straight-up villains who just think they're the good guys.

Examples of Unscrupulous Hero include:

Anime and Manga

In Lupin III, the protagonists are master thieves by trade, but are very strict on what they can or can't do. If there's something threatening the immediate area, they will fight it.
In Slayers Lina Inverse and Zelgadis Graywords both fall in this category in different ways.
- Lina is fully conscious of her status as one of the greatest magical prodigies in the world, and is not above using her vast power to intimidate and extort. Despite this, she exhibits a no-nonsense approach to fighting the forces of evil and she's never shown any real inclination of falling in to the dark side.
- As far is Zelgadis is concerned, he is hell-bent on changing his chimeric body back to normal, and is even nastier than Lina in the intimidate/extort department. Like Lina, though, he will help in saving the world.

Film

The titular Basterds of Inglourious Basterds, and Aldo Raine in particular. Their motivations are heroic, or at least justifiable, but their methods are brutal and sadistic, and they believe wholeheartedly All Germans Are Nazis.
The Blues Brothers, especially Jake. They mean well enough as they just want save the orphanage they grew up in, but they're not above scamming patrons, acting like jackasses and endangering by standers more than they really need to.

Literature

Despite being a straight up bad guy in the films, in the novel Denethor of The Lord of the Rings starts off as a wise ruler dedicated to protecting his kingdom, though he treats his allies with suspicion and verbally abuses his son. Eventually the combined stress of Faramir's coma and his despair send him Jumping Off the Slippery Slope.

Live Action Television

In Veronica Mars, the title character's intent is always to catch the bad guy but her methods can range from manipulating an officer in order to steal evidence or eavesdropping on therapy sessions. Her motivation is almost always revenge rather than justice. She certainly enjoys her Kick the Dog moments, but her targets are always REALLY terrible people so the audience doesn't flinch too much.
Avon of Blake's 7 probably averages out here, especially in series 1 and 3 where he's amoral enough to try and abandon Blake on a Hellhole planet but occasionally shows concern for the others, especially Cally. In series 2 he has enough Pet the Dog moments to push him closer to Good Is Not Nice, but by the final series the stress of maintaining a rebellion he wants nothing to do with turns him into a Nominal Hero.

Western Animation

In El Tigre, although Manuel Rivera is usually on the good guys side, that doesn't stop him from doing mischevious things from time to time.
In Phineas and Ferb, Buford may boast about being a schoolyard bully, but when Phineas and Ferb need help, he can always be counted on.
In Tom and Jerry, although Jerry is generally a Friend to All Living Things, he's definitely not above using violence for reasons other than self - defense or protecting others, often as vengeance for a legitimate wrong, but occasionally, because he's bored. When he does stuff that crosses the Moral Event Horizon, especially when unprovoked, we get a rare Laser-Guided Karma victory for Tom.
If the show wasn't Batman in Batman: The Animated Series, Anti-Villain Mr. Freeze would have been this if not a Byronic Hero or Nominal Hero, since the Corrupt Corporate Executive he was opposing was far worse than he ever was.