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.

Question: What was his career highlights
Self-contained rewrite: What was John Owen Brennan career highlights with the CIA?