After weeks of rumours, confirmation that he had died came shortly after 1am local time. Television stations cut immediately to readings from the Koran, and images of the Qubba, the holy heart of Islam in the Great Mosque at Mecca.
King Abdullah, like his predecessor King Fahd and successor King Salman, was a son of King Abdulaziz al-Saud, who founded modern Saudi Arabia in 1932. He is thought to have left behind four wives and many ex-wives, and around 30 sons and daughters.
Seen as a promising future leader from his youth, he was one of a number of al-Saud's sons to be groomed from an early age with important posts in the country's hierarchy. He led and built the National Guard, the monarchy's equivalent of a presidential guard, and turned it into a power base.
He ruled the country as Crown Prince long before he succeeded to the throne, after his elder brother King Fahd suffered a crippling stroke in 1995. He surprised those who had seen him as a religious and social conservative by pursuing a more open society, within Saudi Arabia's strongly traditional bounds, with a greater freedom and education for women.
For a while, after becoming king, he also allowed greater room for political debate, but closed it off again in the wake of the Arab Spring. The scrutiny long cast on the kingdom's relationship with purist and extremist Islamic thinking was then additionally turned to its human rights record.
A major campaign is under way to stop the 1000 lashes ordered to be inflicted on Raif Badawi, a prominent writer and blogger, for challenging the country's religious authorities.
The king's death comes at a difficult time externally too. His support for the overthrow of President Bashar al-Assad of Syria backfired, leading to a backlash which has seen his adversary, Iran, expand its influence to Saudi Arabia's borders. The kingdom is threatened by the rise of Isis (Islamic State) - and, ironically, blamed in part for its strength, through its laxity in preventing its citizens funding and joining international jihads. Meanwhile, a high-stakes gamble, allowing the oil price to collapse apparently to punish Iran, is also putting pressure on the national budget.
US President Barack Obama expressed condolences to the people of Saudi Arabia upon the death of King Abdullah, an important ally and a major force in the Muslim world. Obama praised Abdullah for taking "bold steps" in advancing the Arab Peace Initiative. He credited the king for being dedicated to the education of his people and greater outreach to the international community.
Obama said he "valued King Abdullah's perspective and appreciated our genuine and warm friendship".
