Also he's really super good-looking.
Anyway, I've been gorging myself on Brando's filmography (in the pursuit of art and knowledge, of course), and here are a few of my very favorites, so far.
On the Waterfront (1954)
The one that started this obsession. In this Elia Kazan film, Brando plays a former prizefighter turned dockworker Terry Malloy who finds himself unwittingly responsible for a young man's death at the hands of corrupt union bosses. Terry has to first stand up to the mafia bosses, including his own brother, and then to his blue-collar community that looks down on snitches, even ones that are trying to help.
Brando won his first Academy Award for this role, and it's truly a great one. He brings the perfect amount remorse, bravado, uncertainty and ultimately determination to the character of a young man who was cut down before he reached his peak, who finds himself part of a world that is repulsive to him, and who tries to do the right thing and is punished for it. Most importantly, this film ushers in a new kind of hero, the kind is imperfect and struggles with his morals.
Julius Caesar (1953)
I like this one because it's so different from what Brando was known for. While he already made a name for himself with A Streetcar Named Desire, he had quite a reputation for mumbling, so pretty much everyone thought Joseph L. Mankiewicz casting him as Mark Antony would be an unmitigated disaster. Instead, Brando practiced by reciting Shakespeare to the fields at his childhood home Omaha, Nebraska, then came back to Hollywood and totally nailed it.
His fiery Mark Antony shows not only his extraordinary skill as an actor but his versatility, and of course his ability to do more than scream "STELLAHHH."
One-Eyed Jacks (1961)
One-Eyed Jacks marks Brando's first and last attempt at directing. That's not to say he did a poor job; in fact, he made a pretty great movie about bank robber who escapes from prison to get revenge on his former friend who betrayed him and became a corrupt sheriff in the meanwhile. He was so dedicated to the film that he would sit for hours by the sea waiting for the waves to become perfectly dramatic for his shots. But Brando wasn't pleased with the final product; for example, he planned a much more dismal ending, with his love interest, the sheriff's daughter, being shot in the back by the sheriff. Instead Paramount Pictures made him change it to make it more promising for the lovers. Brando said of his film, "That's not the picture I made... now the characters are black and white, not gray and human as I planned them."
Even so, Brando did do a great thing by giving us this insult, which I now use frequently: