Your question indicates that you have already formed a very shrewd assessment of the character of Okonkwo. It is very true that he represents a man who is internally divided, and this is most obvious from the way in which Okonkwo responds to his father's life and how he seeks to define himself by what his father was not. As a result, Okonkwo adopts everything that shows him to be a man rather than a weak, lazy individual such as Unoka was. Okonkwo embraces hard work, violence, bravery and success, even going as far as participating in the slaughter of Ikemefuna when he was like a son to him for fear that he might be mocked.
However, the irony of this is that Okonkwo finds himself at conflict again with the society around him and within himself as a result. As the example of Ikemefuna shows, Okonkwo felt driven to participate in his death even when he did not want to. In the same way, just as Unoka found himself in conflict with the tribe around him, so to does Okonkwo discover that he is not able to respond to the differences that are occurring in his tribe, especially when the white men begin to co-exist with the tribe. Okonkwo insists in responding with his customary violence and aggression even when it is clear that compliance becomes the wiser strategy to adopt. Okonkwo thus realises that he is something of an anachronism, unable to move and transform with the changing times.