--- title: H.R. McMaster Is National Security Adviser: What to Know description: President Donald Trump on Monday appointed Lt. Gen. H. R. McMaster to be his new national security adviser. Here's what to know about him canonical: https://time.com/4676669/donald-trump-general-hr-mcmaster-national-security-adviser/ author: Katie Reilly article:opinion: false article:content_tier: free article:published_time: 2017-02-21T13:17:47.000Z article:modified_time: 2026-02-23T03:25:47.798Z article:section: Politics og:title: What to Know About New National Security Adviser Lt. Gen. H.R. McMaster og:description: President Trump has appointed him to replace Mike Flynn og:url: https://time.com/4676669/donald-trump-general-hr-mcmaster-national-security-adviser/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt0209c84877b45f52/6988bb1c97cdff01fa6af8aa/general-mcmaster-what-to-know.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: Donald Trump, H.R. McMaster og:type: article twitter:card: summary_large_image twitter:title: What to Know About New National Security Adviser Lt. Gen. H.R. McMaster twitter:description: President Trump has appointed him to replace Mike Flynn twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt0209c84877b45f52/6988bb1c97cdff01fa6af8aa/general-mcmaster-what-to-know.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  # What to Know About President Trump's New National Security Adviser Lt. Gen. H.R. McMaster  by [Katie Reilly](https://time.com/author/katie-reilly/)  ## Katie Reilly Feb 21, 2017 1:17 PM UTC  President Donald Trump, right, shakes hands with Army Lt. Gen. H.R. McMaster, left, at Trump's Mar-a-Lago estate in Palm Beach, Fla., on Feb. 20, 2017, where he announced that McMaster will be the new national security adviser. President Donald Trump, right, shakes hands with Army Lt. Gen. H.R. McMaster, left, at Trump's Mar-a-Lago estate in Palm Beach, Fla., on Feb. 20, 2017, where he announced that McMaster will be the new national security adviser.Susan Walsh—AP  by [Katie Reilly](https://time.com/author/katie-reilly/)  ## Katie Reilly Feb 21, 2017 1:17 PM UTC [President Donald Trump ](http://time.com/4676427/donald-trump-united-kingdom-british-parliament-debate/)on Monday [appointed Lt. Gen. H. R. McMaster](http://time.com/4676455/donald-trump-h-r-mcmaster-national-security-adviser/) to be his new national security adviser, announcing a replacement for [Mike Flynn](http://time.com/4670930/white-house-president-trump-asked-for-flynns-resignation/), who was [asked to resign last week](http://time.com/4670486/michael-flynn-resignation-record/). Flynn sparked controversy when it was revealed he had misled Vice President Mike Pence about the content of his conversations with the Russian Ambassador to the U.S. Here’s what to know about McMaster: **He comes from a military background** McMaster, 54, is the latest military leader to join Trump’s administration, which already includes two retired generals, Defense Secretary Jim Mattis and Homeland Security Secretary John Kelly. McMaster, who is director of the Army Capabilities Integration Center, will remain on active military duty while serving as national security adviser, the Associated Press reported. He graduated from West Point and earned a doctorate in military history from the University of North Carolina at Chapel Hill. **He was critical of the Vietnam War** McMaster wrote a well-known book in 1997, titled _Dereliction of Duty: Lyndon Johnson, Robert McNamara, the Joint Chiefs of Staff, and the Lies that Led to Vietnam._ He criticized the U.S. government for the Vietnam War and argued that the Joint Chiefs should have pushed back against President Lyndon B. Johnson. “We must address the question of responsibility for one of the greatest American foreign policy disasters of the twentieth century,” he wrote in the book. **McMaster served twice in Iraq** He earned a Silver Star after commanding a unit during one of the most significant battles of the Persian Gulf war in 1991, the [New York _Times_ reported](https://www.nytimes.com/2017/02/20/us/politics/mcmaster-national-security-adviser-trump.html?hp&action=click&pgtype=Homepage&clickSource=story-heading&module=first-column-region®ion=top-news&WT.nav=top-news). He later returned to Iraq from 2005 to 2006, leading an operation to regain control of Tal Afar and serving as special adviser to the top U.S. commander in Iraq, according to the AP. **Republicans praised his appointment** Arizona Sen. John McCain, [who has been critical](https://www.nytimes.com/2017/02/19/us/politics/john-mccain-donald-trump-critic.html) of other aspects of Trump’s administration, called McMaster an “outstanding choice” and a “man of genuine intellect, character, and ability.” “I could not imagine a better, more capable national security team than the one we have right now,” said McCain, a veteran who was held for more than five years as a prisoner of war in Vietnam. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/4676669/donald-trump-general-hr-mcmaster-national-security-adviser/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/4676669/donald-trump-general-hr-mcmaster-national-security-adviser/"},"headline":"What to Know About President Trump's New National Security Adviser Lt. Gen. H.R. 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