A member of the House of Glücksburg, Harald was the third child and only son of King Olav V of Norway and Princess Märtha of Sweden.

He returned to Norway in 1945, and subsequently studied for periods at the University of Oslo, the Norwegian Military Academy, and Balliol College, Oxford.

At the time of Harald's birth, he was second in line of succession to the Norwegian throne following his father, Crown Prince Olav.

The latter party reached Sweden on the night of 10 April, but although Crown Princess Märtha was Swedish-born, they encountered problems at the border station.

[3] However, when the King and Crown Prince inquired of Swedish foreign minister Christian Günther whether they could sleep one night in Sweden without being interned, their request was refused.

[3] Harald spent the following days in Sälen before moving to Prince Carl Bernadotte's home in Frötuna on 16 April.

King Gustaf V has been accounted to have had an amicable relationship with his Norwegian guests, but the topic of the war in Norway was not to be raised.

However, influential Swedish politicians, including Minister of Justice Westman, wanted the Crown Princess and Prince Harald to be sent back to Norway so he could be proclaimed King by the Germans.

[3][4] After the King and Crown Prince had to leave Norway on 7 June they felt Sweden might not be the best place for the rest of the family, and started planning for them to go to the United States.

[3] Harald, his mother, and his sisters lived in Washington, D.C. and Scottsdale, Arizona during the war,[5] while his father, Crown Prince Olav, and his grandfather, King Haakon, stayed in London with the Norwegian government-in-exile.

One of the notable events he remembers from that time is standing behind Franklin D. Roosevelt when he was sworn in for his fourth term on the South Portico of the White House in 1945.

[6] The Doris Kearns Goodwin book No Ordinary Time: Franklin and Eleanor Roosevelt and the Home Front in World War II contains a picture of the King (then Prince) playing with FDR's dog, Fala, on the North Lawn of the White House in 1944.

In the autumn of 1945 he was enrolled in third grade of Smestad skole as the first member of the royal family to attend a public (state) school.

The Crown Princess's death was a tremendous loss for him and his family as well as for Norway,[7] and he named his daughter Märtha to honour her memory.

On 21 September 1957 at the death of his grandfather, Harald became crown prince at the age of 20 and he attended the Council of State for the first time six days later and took the oath to the Constitution of Norway on 21 February 1958.

In 1960, he also made his first official journey abroad, visiting the United States in connection with the fiftieth anniversary of the American Scandinavian Foundation.

An avid sailor,[8] Harald represented Norway in the yachting events of the Summer Olympics in Tokyo in 1964,[9] Mexico City in 1968,[6] and Munich in 1972.

The couple had two children, Princess Märtha Louise and Crown Prince Haakon, heir apparent to the Norwegian throne.

King Harald's decision to accept two more commoners into the royal family, Crown Princess Mette-Marit and Ari Behn, has been interpreted as a sign of modernization and adjustment.

When the parliamentary situation is unclear, the King relies on the advice of the President of Parliament and the sitting prime minister.

In July 2005, the King and his crew aboard the royal sailboat Fram XV won the gold medal at the European Championships in Sweden.

Crown Prince Haakon served as the country's regent on these occasions, including giving the King's Speech at the State opening of parliament in 2020.

The new venue was named The Queen Sonja Art Stable and is the first institution owned by the royal family which is permanently open to the public.

On 31 January 2024, the royal palace announced that King Harald was on "sick leave" until 2 February due to a respiratory infection.

He was discharged on 3 March and was transported back to Norway on a medical evacuation flight to continue his recovery in a hospital, during which he would be on sick leave for two weeks.

Harald is in the line of succession to the British throne, because of his descent from King Edward VII of the United Kingdom.