His name is most closely associated with nationalist Egyptian President Gamal Abdel Nasser in the 1960s.
Mr Heikal was the editor of Egypt's state-owned newspaper, Al-Ahram, during that time, articulating the Nasserist ideology of "Arab socialism".
He also served as information minister and briefly as foreign minister.
Following Nasser's death in 1970, Mr Heikal was sidelined by his successor Anwar al-Sadat. And in 1981 he was jailed along with hundreds of government critics.
He was released by Hosni Mubarak after Sadat's assassination by Islamist militants later that year, but was kept at arm's length by the president throughout his 29 years in office.
But Mr Heikal remained for decades one of the most authoritative commentators on Egypt and the Arab world - as well as a historian of the tumultuous events of the Nasser area.
Announcing Mr Heikal's death on Wednesday, Al-Ahram said he been ill for three weeks, and had suffered fluid on the lungs and kidney failure.
President Abdul Fattah al-Sisi paid tribute to Mr Heikal, calling him a "journalistic icon", while the cabinet said he had "massively participated in enriching intellectual life with his books, articles, political and historical studies", Egypt's ON TV Live reported.
One of the most famous and influential journalists in the Arab world, the Egyptian Mohamed Hassanein Heikal, has died in Cairo at the age of 92.