This is a political novel - is it satire? I don't know. It's not obviously humourous, but it is infused with a wry understanding of human foibles.
This is the story of the political disintegration of an unnamed African country that's really Nigeria. His main character, Odili, is an idealistic young man who becomes acquainted with his government representative Chief Nanga and decides to challenge him for office. Chief Nanga uses various pressure tactics to dissuade Odili and other members of his new political party. Meanwhile, corruption scandals cause governmental chaos and ends in a military coup (A Man of the People was published just before the 1966 military coup in Nigeria).
The key tension in the book is provided by Odili's expections - of himself, Chief Nanga, his father, his community - all of which are disappointed. He expects Nanga to ignore him, but he finds him charming, charismatic and helpful. He expects himself to be pure and selfless; but in reality he enjoys very much driving around his party car, and he originally turns against Nanga not because of his corruption, but because Nanga sleeps with his girlfriend. He expects his father to be hostile to his political ambitions; instead his father encourages him and refuses to bow to local pressure. He expects his community to object to the rampant government corruption; they don't. In the end I'm not sure whether the title refers to Chief Nanga's extreme popularity or Odili's unwillingly acknowledged similarities to the countrymen he finds so frustrating.