In The Stranger, Meursault is Camus' absurdist (similar to existentialism) hero: he loves life, hates death, and scorns the gods. Instead of crying at his mother's funeral, he refuses to participate in the morbid culture of death. Instead, he loves his freedom, weekends frolicking in the ocean with Marie. In Part II, Meursalt scorns the chaplain and the court, both forces of determinism. He refuses to feel their imposed guilt.
Meursault is no friend of the feminists. He helps Raymond write a letter to get Raymond's Arab girlfriend back so that he can take revenge on her (physical abuse). Meursault, however, does treat Marie as a modern woman: he spurns talk of marriage, instead favoring an open relationship.
Meursault suffers from the Oedipal complex. He loves his mother so much that he is in denial of it. This is why he refuses to even see her face before she is buried. Because he suffers from Oedipal guilt, he takes out his rage on threatening male-figures (not his father, but the Arab).
In Marxist theory, Meursault is a hero to the proles. He is a working class hero. First, he hates menial labor, and he refuses a promotion to France that his boss offers. Instead, Meursault refuses to be corrupted by greed and false dreams.