Michael Thomas Flynn is a retired United States Army lieutenant general who was the 24th U.S. national security advisor for the first 22 days of the Trump administration. He resigned in light of reports that he had lied regarding conversations with Russian ambassador to the United States Sergey Kislyak. Flynn's military career included a key role in shaping U.S. counterterrorism strategy and dismantling insurgent networks in the Afghanistan and Iraq Wars, and he was given numerous combat arms, conventional, and special operations senior intelligence assignments. He became the 18th director of the Defense Intelligence Agency in July 2012 until his forced retirement from the military in August 2014. During his tenure he gave a lecture on leadership at the Moscow headquarters of the Russian military intelligence directorate GRU, the first American official to be admitted entry to the headquarters.

The Director of the United States Defense Intelligence Agency is a military officer who, upon nomination by the President of the United States and confirmation by the Senate, serves as the United States' highest-ranking military intelligence officer. As the head of the Defense Intelligence Agency, the Director is the principal intelligence adviser to the Secretary of Defense and the Chairman of the Joint Chiefs of Staff. The Director also reports to the Director of National Intelligence, via the civilian Under Secretary of Defense for Intelligence.