Cambodian politician, king 1941–55 and 1993–2004. He was prime minister 1955–70, when his government was overthrown in a military coup led by Lon Nol. With Pol Pot's resistance front, he overthrew Lon Nol in 1975 and again became prime minister 1975–76, when he was forced to resign by the Khmer Rouge. He returned from exile in November 1991 under the auspices of a United Nations-brokered peace settlement to head a coalition intended to comprise all Cambodia's warring factions (the Khmer Rouge, however, continued fighting). He was re-elected king after the 1993 elections, in which the royalist party won a majority; but Hun Sen of the Cambodian People's Party effectively took power from 1997 after engineering a coup against the royalists. In October 2004 Sihanouk abdicated for health reasons and was succeeded by one of his sons, Norodom Sihamoni.
Educated in Vietnam and Paris, he was elected king of Cambodia in 1941. He abdicated in 1955 in favour of his father, founded the Popular Socialist Community, and governed as prime minister 1955–70.
After he was deposed in 1970, Sihanouk established a government in exile in Beijing and formed a joint resistance front with Pol Pot. This movement succeeded in overthrowing Lon Nol in April 1975 and Sihanouk was reappointed head of state, but was forced to resign in April 1976 by the communist Khmer Rouge leadership. Based in North Korea, he became the recognized head of the Democratic Kampuchea government in exile in 1982, leading a coalition of three groups opposing the Vietnamese-installed government. International peace conferences aimed at negotiating a settlement repeatedly broke down, fighting intensified, and the Khmer Rouge succeeded in taking some important provincial capitals.
A peace agreement was eventually signed in Paris on 23 October 1991. On his return from exile, Sihanouk called for an international trial of the leaders of the Khmer Rouge on charges of genocide. His son, Prince Norodom Ranariddh, became prime minister in July 1993. In October 1993 Sihanouk was crowned king under a new constitution providing for an elected monarch with limited powers. During 1994 there were a number of attempted coups against him, led by his close relatives.