How is Chris McCandless portayed as noble or wise thoughtout Into the Wild?

This is an interesting question. Certainly Chris draws many different reactions from different people. I suppose there is something noble about leaving this materialistic vanity obsessed culture for a simpler, more "real" existence. Our society can be suffocatingly artificial and shallow. Chris wanted to follow in the footsteps of writers like Thoreau and Emerson; he wanted to live deliberately and for the moment. Chris is celebrated by many as a counter-cultural messiah of sorts. He tries to find truth in the moments that he lives rather than the stale memories of the past and the illusions of the future. Chris picks up pieces of wisdom here and there. He is able to connect with many people on his journey but not own the relationship as many of us try to do. That's sort of the persuasive part you asked for. I think the way Chris went about his self-discovery was anything but noble but I suppose that's another topic.