Hassanal Bolkiah was born on July 15, 1946 in Brunei Town in Brunei. He is the eldest son of the previous Sultan Omar Ali Saiduddien III. At the age of 15, in 1961, he became the formal successor to the throne of Brunei. He was educated in Brunei and Malaysia, and in the years 1966-1967 he underwent an officer training at the Royal Military Academy in Sandhurst.
After his father's abdication, he was proclaimed Sultan Brunei on October 5, 1967. His coronation took place on August 1, 1968.
In 1978, he held talks with the British Queen regarding the change of Brunei status, which resulted in the signing of a treaty of friendship and cooperation between Brunei and the United Kingdom, in which the British government renounced Brunei's foreign and defense policy. On January 1, 1984, Brunei gained independence and the Sultan became prime minister of the newly formed government. After his father's death in 1986, he became the minister of national defense. After the dismissal of Brother Jefri in February 1997, he also took the post of Minister of Finance. In October 2015, he took over the brother of Mohamed as a minister of foreign affairs and trade.
From July 1965, Hassanal Bolkiah is married to his cousin Saleha, who bears the royal title of Raja Isteri Pengiran. In 1981, he married the second wife Mariam Abdul Aziz, with whom he divorced in 2003. From August 20, 2005 to June 16, 2010, the Malaysian TV3 journalist Azrinaz Mazhar Hakim was the third sultan's wife, who on 1 June 2006 gave birth to the son of Prince Abdul Wakeel and on January 28, 2008, the daughter of Princess Ameerah Wardatulę Bolkiah. On June 9, 2009, she received the title of Queen Pengiran Isteri. The Sultan divorced her, depriving her of all royal titles, decorations and medals. Hassanal Bolkiah has five sons and seven daughters. In August 1998, he established the formal successor to the throne of his eldest son, Billah.
Sultan is considered one of the richest people in the world. In 2011, Forbes magazine estimated its assets at USD 20 billion.