Okonkwo is famous because of how he is able to define his identity in conjunction with socially established norms of "success." Okonkwo makes himself in the Igbo image of success. He defines himself through his notable strength, vision of masculinity, and in being what others deem as a "success." He is a strong warrior, able to defeat worthy adversaries, and defend that which is his. He shows this with his defeat of Amalinze, someone who had remained undefeated for years. His reputation as a wrestler is something of legend. He is also famous for being economically successful. Okonkwo is able to generate wealth through his own prowess and skill, reflective in his advancements in farming. In marrying three women and serving as father to many children, the Igbo notion of strength and success are parts of Okonkwo's identity. He demonstrates success to such a degree that he is famous for his accomplishments, moving him closer to having titles of respectability conferred upon him.
Okonkwo is also famous because he actively defines himself in opposition to his past. Okonkwo is driven to craft his identity in stark opposition to his father. Where his father had debt, Okonkwo refuses to hold any situation which could develop as a debit. Where his father was lazy, Okonkwo is strong and focused. Okonkwo develops a name for himself by not being scared of things, like war and conflict, that had scared his father. Okonkwo embodies family responsibility where his father abandoned them. While his father was "soft" and deemed as unmanly, Okonkwo defines himself as the archetype of what it means to be a man. In this regard, Okonkwo is famous for being everything his father is not. In these ways, the exposition of the novel establishes why Okonkwo is famous.