The Emmy-nominated actor told Entertainment Weekly that the conflicted former marine will be on an "accelerated political trajectory" in future episodes.
"Brody makes a mission statement to Abu Nazir at the end of season one when he says, 'I have decided non-violence is the way forward'," he explained.
"And he seems to say at that point that you have not successfully radicalised me to act violently, but I do still hold this personal grudge towards the Vice President (Jamey Sheridan)."
He concluded: "Brody is clearly still vulnerable and unstable. He accepts the job because it gets him to be closer to the man he needs to be closer to - the Vice President."
Homeland has been nominated for a total of 9 Emmy awards, including nods for Lewis and co-star Claire Danes (Carrie Mathison).
The series will return to Showtime in the US on September 30. Season two is expected to debut in the UK in October.
Watch Homeland's executive producer Howard Gordon discuss the show below: