Okonkwo's exile is ironic in that Okonkwo leaves and everything in his village changes. While Okonkwo is away, the white man comes in and begins converting more men from Umuofia to Christianity. It is ironic in that Okonkwo seemed to be holding his village together. He in all his fierceness served as a leader who kept Umuofia safe from the intruders. Now, ironically, in Okonkwo's exile, he loses his standing in both places.
In the seven years that Okonkwo was exiled, things began falling apart in his village. In only seven years, Okonkwo does not recognize his village. The irony is in the fact that Okonkwo cannot get his village leaders to go to war. To have a been such a strong leader, now Okonkwo has lost his authority.
Another example of irony is that Okonkwo took Ikemefuna into his own home. Now, Okonkwo understands how Ikemefuna feels having to leave his homeland. The irony is in the fact that Okonkwo becomes an exile just as Ikemfuna. Ikemefuna left his home behind, not knowing what to expect. In much the same way, Okonkwo has left his home behind not thinking that so much will change in his absence.
The irony is that Okonkwo blames everything on his chi. He does not take responsibility for his own actions:
When Okonkwo is in exile, he ponders the tribe's view of his chi. He thinks that maybe they have been wrong—that his chi was not made for great things. Okonkwo blames his exile on his chi. He refuses to accept that his actions have led him to this point. He sees no connections among his breaking the Week of Peace, his killing Ikemefuna, and his shooting Ezeudu's son. In Okonkwo's eyes, his troubles result from ill fate and chance.
Ironically, these are the opposite actions of a strong leader. Okonkwo is not as strong as he appears. He cannot handle it when the village will not go to war. Ironically, Okonkwo leaves his village a strong man. He comes back and is not as strong as he once was. He hangs himself because his village is falling apart. Ironically, he dies without honors, just like his father.