Everything you need to know about National Security Adviser Michael Flynn

Retired Lt. Gen. Michael Thomas Flynn has been selected by President-elect Donald Trump to serve as National Security Adviser.

Flynn is a 33-year Army veteran who served as Director of the Defense Intelligence Agency during the Obama administration from 2012-2014. He was fired from his position and has since become a critic of President Obama's foreign policy.

According to ABC News, he worked as an informal political adviser on national security issues for Trump's presidential campaign.

Learn more about Flynn from ABC News.