Herbert Raymond “H.R.” McMaster served as the 26th national security advisor. He served in the Trump administration from February 20, 2017, to April 9, 2018.
McMaster, a three-star lieutenant general in the United States Army, was the first active duty military officer to serve in the position since General Colin Powell, who served in the Reagan administration from 1987 to 1989.
The assistant to the president for national security affairs (APNSA), commonly known as the national security advisor (NSA), is part of the National Security Council (NSC). The NSC “is the President’s principal forum for considering national security and foreign policy matters with his senior national security advisors and cabinet officials. Since its inception under President Truman, the Council’s function has been to advise and assist the President on national security and foreign policies. The Council also serves as the President’s principal arm for coordinating these policies among various government agencies,” according to the White House.