The White House would not say whether Harvey was sacked, but confirmed he will no longer serve as the top Middle East adviser.
"The administration is working with Colonel Harvey to identify positions in which his background and expertise can be best utilized", National Security Council spokesman Michael Anton told the Weekly Standard.
Harvey was initially hired for the council by Lt. Gen. Michael Flynn, who has also been sacked, and may not have been favored by H.R. McMaster.
A statement issued by NSC spokesman Michael Anton said that McMaster "greatly appreciates Derek Harvey's service to his country". And yet, Harvey has positions that don't quite square up with Bannon's normal non-interventionist approach to foreign policy.
The retired Army colonel has vast experience in Middle East conflicts, helping lead counterinsurgency efforts in Iraq and Afghanistan as a key official at U.S. Central Command and the Defense Intelligence Agency.
"This has been work of vital importance to our country, and my departure comes with mixed emotions".
But while Harvey's future in the administration remains unclear, a spokesperson for the NSC confirmed that his ouster was not the result of a mutual decision, telling reporters it was fair to say he was "removed".
"I will be leaving the National Security Council today to take advantage of a new opportunity to continue serving our President and the United States of America in an important capacity", he said, though didn't specify what the new opportunity is.
In addition to the tension between him and these two White House officials, TWS also cites Harvey's close relationship with White House strategist Steve Bannon as a reason for his dismissal. When he still served as national security adviser, Flynn placed both McFarland and Cohen-Watnick on the NSC. He served as senior director for Middle East policy on the NSC. Keane told NBC News he was "befuddled as to why he is being removed".