Councillor Hamann was a senior member of the Zion Council.
Hamann was trapped in the Matrix until he was eleven years old and was released. He later claimed that this resulted in him developing a distaste for sleep, feeling that he spent the first eleven years of his life sleeping and was now making up for it.
While Neo was staying in Zion and having trouble sleeping, he and Hamann went to the industrial level and had a conversation about control, agreeing with Neo's assessment that the ability to control something could be measured by their ability to turn it off. There Hamann admitted to Neo that, just as he trusted that the machines underneath Zion supported them even if he couldn't understand how some of them worked, he trusted that Neo's talents would help them win the war although he could not understand their nature.
He later clears the Nebuchadnezzar to enter the Matrix so they could contact the Oracle, despite Commander Lock's wishes, noting in response to Lock's objections that he believed that Zion's survival would depend on more than just how many ships they possessed.
He is only shown with other council members in subsequent scenes, although he is shown directly when he asks the Kid for the reason for his excitement after the Sentinels withdraw from Zion following Neo's defeat of Smith.
Councillor Hamann's name may have been taken from Johann Georg Hamann, a German philosopher who was convinced that faith and belief, beyond knowledge, determine human actions (passion affects reason). He liked to think of contradictions and irrationalism and took the famous Socrates quote: "As for me, all I know is that I know nothing" as an example of irrationalism.