After the short, tumultuous reign of National Security Adviser Michael Flynn, President Donald Trump is clearly in the mood for another maverick military man with his choice for his replacement: Lt. Gen. H.R. McMaster.

Described a leading intellectual of the US Army, McMaster is known for his free strategic thinking, his surprising rise as a soldier and, above all, as a seminal iconoclast.

Born Herbert Raymond McMaster, the new national security adviser began his days in Philadelphia, Pennsylvania. He graduated from military high school in 1980 and went on to the military academy at West Point. Showing his intellectual credentials, he received an MA and PhD in American History from the University of North Carolina at Chapel Hill.

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While serving in the US Army during the first Gulf War, McMaster famously captained a troop of nine tanks in a battle against over 80 Iraqi Republican Guard tanks and vehicles. His troop took no losses: the same could not be said of the enemy. His captaincy saw him awarded the Silver Star.

In 1997, his PhD thesis became the book Dereliction of Duty - a harsh critique of US policy and senior officials during the Vietnam War. It has since become a major text that had added to his reputation.

McMaster spent time in different roles at US Central Command before taking command of a cavalry regiment in Iraq during the second Gulf War. He went on to join a London-based strategic institute and then advised General David Petraeus - one of the candidates passed over for the role McMaster has now taken.

In 2014, he was promoted to lieutenant general and a month later was named as one of Time magazine's 100 most influential people in the world. In an article for the list, retired Lt. Gen. Dave Barno said that McMasters had been passed over for promotions, made senior Army officials wonder how to oust him, and still survived.

Described by Barno as having "impressive command and unconventional exploits", the military man is now advising a similarly unconventional US President. Whether there are clashes, or whether the position of White House Chief Strategist Steve Bannon, now given a permanent role on the National Security Council, causes new problems, is yet to be seen.

Donald Trump