Here is something from Wikipedia I did not know:
In September 2011, Flynn was promoted to Lieutenant General and assigned as assistant director of national intelligence in the Office of the Director of National Intelligence. On April 17, 2012, President Barack Obama nominated Flynn to be the 18th director of the Defense Intelligence Agency.[28][29] Flynn took command of the DIA in July 2012.[30] He simultaneously became commander of the Joint Functional Component Command for Intelligence, Surveillance and Reconnaissance, and chair of the Military Intelligence Board.
In October 2012, Flynn announced plans to release his paper "VISION2020: Accelerating Change Through Integration", a look at changes he believes are necessary for the DIA in the future.[31][32]
In June 2013, Michael Flynn became the first U.S. officer to be allowed inside the Russian military intelligence (GRU) headquarters in Moscow, where he arrived at the invitation of the GRU chief Gen Igor Sergun.[33][34] His follow-up trip to visit the GRU HQ as Director of DIA was not allowed.[34]
Stefan Halper, who worked for three Republican presidents and was a longtime informant for the American intelligence community, had a February 2014 encounter with Flynn at a London intelligence conference. Harper became so alarmed by Flynns close association with a Russian woman that a Halper associate expressed concerns to American authorities that Flynn may have been compromised by Russian intelligence. Flynn was forced out of the DIA six months later, although public accounts at the time cited other reasons for his removal, including his management style and views on Islam. Halper was later a central figure in Spygate, a conspiracy theory initiated by President Donald Trump that asserted the FBI had planted a spy in his 2016 campaign.[35]