The white guy is always the hero, right? Well, that's what they want us to believe, anyway. There are a ton of movies in which the person you think is the protagonist, the one whose face is all over the posters and advertisements, the one who appears on all the talk shows and gets the most screen time, in fact serves a role other than that of protagonist. This mostly comes down to how the roles of characters are defined. When you get down to brass tacks, there are a lot of unlikely movie heroes out there.
You have your movies where the hero isn't really a hero at all, and movies in which the protagonist isn't the main character. There are even cases in which the purported villain of the movie is really more of a hero or protagonist than main character. But what does this all mean? You can define "protagonist" is various ways - the central character in drama, for instance. However, this is a bit vague. This list sticks to the definition employed by most commercial screenplays, in which the protagonist is the character with the most urgent dramatic want or the most pressing physical goal.
Here's how heroes and protagonists differ. A hero is a central character that displays admirable qualities and most often supports the emotional heft of a movie, giving action to the film's foundational themes. (Of course, sometimes a hero's most emotional moments end up on the cutting room floor.) As many films have shown over the years, it's not necessary for the hero to be the protagonist. Take, for instance, The Lion King. Simba's physical goal is to stay hidden with Pumba and Timon. Nala's is to save her society from starving. Who has the more pressing problem there? But Simba is most certainly the central character.
The point is, we don't always have to accept the white guy around whom a movie revolves is the protagonist. Here are some movies with supporting characters who were actually the hero, or those in which the protagonist isn't at all who you thought it was. BTW, don't be surprised how many of these characters are female.
Frodo kinda sucks, right? As Sam and Frodo's journey progresses over the course of the Lord of the Rings trilogy, Frodo is increasingly ensnared by the power of the ring. He eventually casts Sam off, and gives in to the ring's call. The battle would have been lost right then and there if Sam hadn't saved the day. In that sense, and as the character who most frequently voices the moral heart of the saga, Sam is the hero of the trilogy.
Regardless of his hero status, Sam is the most obvious candidate for the protagonist of the Lord of the Rings films. Frodo is sent on a mission, which makes him something of a passive character. Throughout his journey, he gets pointed this way and that by people around him. Sam, on the other hand, elects to take every step in his journey. His goal is to protect and aid Frodo, thus ensuring the ring gets destroyed. The destruction of the ring is the primary physical goal of the series, so while Frodo is shouldered with the burden, and has one very heroic moment of leadership, Sam is true protagonist, who volunteers to ensure the safety of the ring bearer and success of his goal.
If you watched Mad Max: Fury Road without knowing the title, you would conclude Furiosa is the protagonist. She smuggles concubines away from a tyrant so they can have a better life, away from the controlling machinations of a brutal patriarchy. She's pursued by an entire army as she tries to get them to safety. That's pretty much the entire film.
There's also this guy named Max (Tom Hardy) who reluctantly helps Furiosa so he can escape the same tyrant, but the plot is very much driven by Furiosa's actions and goals, and her moral righteousness gives the movie its heart. Given the title and that Tom Hardy is listed first on IMDb, it would be easy to conclude Max is the protagonist. He isn't.
John and Sarah Connor share the bulk of screen time in Terminator 2, but, until the third act, when Sarah takes charge, the film's protagonist is the titular robot. Maybe this isn't a surprise, since the movie is named after him and he's front and center on all the key art, but watching the movie, he mostly seems like a prop in the harrowing human drama at the center of the narrative.
What's Terminator 2 really about? Until Sarah decides to go after Miles Bennett Dyson to stop Skynet before it starts, protecting John and Sarah Connor from a liquid metal robot assassin from the future, T100. The Terminator played by Arnold Schwarzenegger is tasked with that project. He also provides a robot father figure for wayward youth John, who spends his time riding around on a dirt bike robbing ATMs while listening to Guns N' Roses.
Simba is a tool. At least, you can reasonably view him as such, in an almost literal sense. He runs off in his youth and gets lost (okay, fair enough, his dad died and he thinks it's his fault), then grows up with a couple self-indulgent fellows in what seems like a three person hippie commune. He grows his hair out and doesn't have purpose. All the while, Nala is back with the pride. Living under a tyrant, she takes it upon herself to go into the jungle in search of anything or anyone that can help unseat this dictator, and to find food, so the entire pride doesn't starve to death.
Nala finds Simba and convinces his lazy ass to come back with her. Unlike Simba, Nala has a strong physical goal, while fully embodying the emotional subtext and themes of The Lion King. If she had found a different exiled lion who she convinced to help and never came across Simba, would Simba ever have done anything? Doesn't seem like it.