White-Haired Pretty Boy "Adonis is one of the main characters this thing circles around, but he does have one distressing feature. SILVER HAIR. This means nothing good can come of him. YOU KNOW THE RULE ABOUT SILVER HAIR."
— Zarla, Let's Play: Silver Chaos
If he's lucky, he's an Anti-Hero. He's much more likely to be the Lovable Traitor, a Trickster, or The Rival. But usually he's just a villain, sooner or later. He will be aloof, often speaking cryptically and ending every sentence with a flip of his hair and a smirk. If he wears glasses, they'll glow often. Or he'll be quiet and shy, barely cracking a smile, yet he'll still be able to thoroughly kick your ass. Sometimes, in recent cases, he'll show bisexual tendencies, more likely if he's the bad guy. He'll have special powers, since white hair on a young person who isn't albino is rare. Which makes you wonder about the red eyes... If he's a good guy, he'll still seem aloof most of the time.
Despite the wide range and use of Hair Colors for characters, there's an eerie specificity to the use of white (silver works too, but not blonde) hair when coupled with a handsome, vaguely effeminate face. The (usually long and rarely tied back) white hair is very frequently coupled with red eyes. This character will never be as morally set in his ways.
Within anime, this may have a cultural explanation. White skin is considered attractive in nobility and women, but glaring white is otherwise commonly associated with death.
For some reason this trope applies much more strongly in shows with predominantly male audiences than to something like shojo, where the character will still tend to be aloof, shy, or outright eerie.
White haired guys with dark skin (such as ∀ Gundam's Loran) are typically exempt, because it's often used as a simple contrasting color like blonde or red hair. Occasionally, perhaps to preserve the white=death rule, foreigners are exempt from this too.
Commonly prone to Minor Injury Overreaction. Compare with Blond Guys Are Evil and Evil Albino, which are more western alternatives of this trope. Compare and contrast with the Distaff Counterpart, the White-Haired Pretty Girl, who is less likely to be evil and more likely to be magical.
Expect a White-Haired Pretty Boy to have a good share of fangirls, or even be subjected to Misaimed Fandom.