McMaster's no lightweight. The PhD has criticised the Vietnam War, and has said that the "Islamic State is not Islamic."
US President Donald Trump has appointed Lt Gen HR McMaster as his national security adviser, following Michael Flynn's ouster 24 days into his post after misleading the vice president about contacts with Russia.
McMaster has no known links to Trump – unlike Flynn who served as a campaign adviser last year. He flew back to the Washington area from Florida with Trump on Air Force One, and will remain on active military duty, the White House said on Monday.
1. McMaster is a military tactician and a strategic thinker. The 54-year-old McMaster is the first active-duty military officer to take the post since General Colin Powell. He served in the Persian Gulf War, as well as the wars in Afghanistan and Iraq.
A combat veteran, he gained renown in the first Gulf War – and was awarded a Silver Star – after he commanded a small troop of the US 2nd Armored Cavalry Regiment that destroyed a much larger Iraqi Republican Guard force in 1991 in a place called 73 Easting, in what many consider to be the biggest tank battle since World War Two. He's now the director of the Army Capabilities Integration Center and Deputy Commanding General, Futures at US Army Training and Doctrine Command.
McMaster, who received a PhD in history from the University of North Carolina, gained fame after writing his 1997 book, "Dereliction of Duty," which criticised the country's military and political leadership for miscommunication during the Vietnam War.
2. He wasn't Trump's first choice. Vice Adm Robert Harward was initially offered the position, but he turned it down amid concerns about how the White House was being run, CNN reported.
The post was vacated after it was revealed that Donald Trump's first pick, Michael Flynn, allegedly misled the vice president by his failure to report his conversation with Russian ambassador to the US, Sergey Kislyak. Flynn was asked to resign 24 days into his position.
Flynn's actions bring to mind his call for Democratic Presidential Nominee Hillary Clinton to drop out of the race during the Republican National Convention in July because she had "put our nation's security at extremely high risk." He also called officials to "lock her up."
3. Trump and McMaster might differ on Russia: Trump in the past has expressed a willingness to engage with Russia more than his predecessor, Barack Obama.
But this is a subject on which Trump and McMaster could soon differ. McMaster shares the consensus view among the US national security establishment that Russia is a threat and antagonistic towards the United States, while the man whom McMaster is replacing, retired Lt Gen Michael Flynn, appeared to view Russia as a potential geopolitical partner.
4. He's not afraid to question his boss: McMaster has a reputation for speaking his mind within military ranks, according to CNN. This has raised questions about his slow advancement in his successful military career – he hasn't refrained from writing about military strategy and has criticised high-ranking officials. This attitude was not always shared by his superiors. It led to his being passed over for promotion to brigadier general twice, in 2006 and 2007.
A former US ambassador to Russia under Obama, Michael McFaul, a Democrat, praised McMaster on Twitter as "terrific" and said McMaster "will not be afraid to question his boss."
5. He believes the military is impervious to criticism: In a July 14, 2014, interview with the Columbus Ledger-Enquirer in Columbus, Georgia, where Fort Benning is located, McMaster, then the base commander, said: "Some people have a misunderstanding about the Army."
"Some people think, hey, you're in the military and everything is super hierarchical and you're in an environment that is intolerant of criticism and people don't want frank assessments. I think the opposite is the case ... And the commanders that I've worked for, they want frank assessments – they want criticism and feedback."
6. He's immersed himself in ground realities during battles: McMaster's preparation of his regiment is legendary. He trained his soldiers in Iraqi culture, the differences among Sunnis, Shi'ites and Turkmen, and had them read books on the history of the region and counterinsurgency strategy.
It was a sharp contrast to the "kill and capture" tactics the United States had used in Iraq since the invasion in March 2003, and to which the Obama administration returned in Afghanistan, Iraq and Syria.
The strategy was largely a success, although McMaster's use of it – his willingness to acknowledge that Iraqis had some legitimate grievances against one another as well as the occupying coalition forces — did not endear him to his superiors and helped delay his promotion.
The strategy did not survive the departure of McMaster's troops, with Tal Afar falling into the hands of Sunni militants. During a speech at National Defense University in Washington, he said that "the Islamic State is not Islamic."
7. His appointment has met with praise from both Democrats and Republicans:
McMaster is a good pick, but the glaring lack of Asia expertise among senior national security officials remains a major Achilles' heel.— Ely Ratner (@elyratner) February 21, 2017
World may be a slightly safer place ts morning. Newly appointed US Natl Sec Adviser LtGen HR McMaster is highly intelligent, thoughtful man.— Frank Gardner (@FrankRGardner) February 21, 2017
Dems would be less alarmed if @realDonaldTrump surrounded himself (and listened to) people like HR McMaster rather than Bannon and Miller.— Peter Daou (@peterdaou) February 21, 2017