Conversation so far:
What was John Owen Brennan's career?
John Owen Brennan served as the Director of the Central Intelligence Agency (CIA) from March 2013 to January 2017.
What did John Owen Brennan do as director of the CIA?
He defended the CIA's past interrogation tactics as having yielded useful intelligence, during a news conference.
What was John Owen Brennan career highlights with the CIA?
Brennan created ten new mission centers in his campaign to focus the CIA on threats in cyberspace, where analysts and hackers work in teams.
Are there any other interesting aspects about the John Owen Brennan article?
Brennan left government service for a few years, becoming CEO of the analysis corporation.

Question: How long was he chairman
Self-contained rewrite: How long was John Owen Brennan chairman of the Intelligence and National Security Alliance?