Aragorn begins Fellowship as the reigning monarch of "the rangers," actually a dispersed nation. They call him Chief to outsiders but his people know who he is and what he hopes to become. I reread the books pretty recently and this was one of the most surprising things that I forgot/got overwritten by movie characterization. He was never a nobody, by the time we meet him he is 40 years into the project of preparing himself for a great trial and then kingship.