Trump was greeted by the Queen on the West Terrace of Buckingham Palace, her official London residence.
Prince Charles and his wife Camilla were the first members of the royal family to meet Trump as he left his official helicopter, which landed in the grounds of the palace.
The American national anthem was played as the royal party and their guests stepped from the palace, and Trump was invited to inspect the guard of honor.
Observers were keen to analyze the moment after commentators suggested the Queen’s choice of fashion accessories had previously revealed her true opinion of Trump.
Ahead of the inspection, Trump’s daughter Ivanka was spotted peering from the balcony of the White Drawing Room overlooking the garden, alongside her husband — the president’s adviser Jared Kushner.
National security advisor John Bolton and press secretary Sarah Huckabee Sanders were also seen in attendance.
Among the soldiers, who when not performing ceremonial duties are fighting servicemen, was Guardsman Joshua Young-Hastings from Wandsworth, south London.
He was the tallest soldier in the guard of honour and played American Football for the London Warriors before joining the Army.
The guardsman was scouted for a professional career with America’s National Football League and was awarded a half scholarship with a Texas university but chose the Grenadier Guards over a sporting career.
During Trump’s welcome ceremony, a series of gun salutes took place in Green Park, near the palace, and the Tower of London, around 2.8 miles to the east.
Eighty-two rounds were fired in Green Park, equal amounts for both Trump’s visit and the anniversary of the Queen’s 1953 coronation, while 103 rounds were fired at the Tower.
The president, accompanied by the Prince of Wales, inspected the guard before the British national anthem was played.
Trump will have a private lunch with the Queen and view a special exhibition of items of historical significance to the United States from the Royal Collection.
Later, accompanied by Prince Andrew, the Trumps will visit Westminster Abbey for a tour, and the president will lay a wreath at the Grave of the Unknown Warrior.