In 1950, he married Yen Dinh, with whom he had a daughter. His first wife died in 2004, and he married Ann Chastain of Eureka, California, in 2005. In 2012, they divorced. His daughter, Yen Khanh, and an adopted son, Tran Khan, as well as a granddaughter, survive him.
The late 1950s and early 1960s were a period of autocratic and nepotistic rule by South Vietnam’s American-backed president, Ngo Dinh Diem, who favoured Catholics in many fields in a largely Buddhist country. His refusal to allow elections in 1956 contributed to the Vietnam War. Colonel Khiem was promoted to general after crushing a coup against his godfather, Mr. Diem, in 1960.
However, in what the Kennedy administration and General Khiem expected to be a nonviolent coup, other Vietnamese military plotters arranged for President Diem to be deposed and killed in an armoured personnel carrier en route to the airport and an expected exile abroad in 1963.
Short-lived juntas were deposed by coups in the aftermath of the assassination. General Khiem briefly served as a member of the ruling junta before being sent into political exile as ambassador to the United States in 1964. He plotted with Saigon generals to seize power from Washington. On the day of a planned coup, however, he forgot to set his alarm clock and overslept. The coup was carried out without him and failed.
Mr. Khiem was appointed ambassador to Taiwan by another junta in 1965, which included General Thieu and General Ky. In 1968, he was returned to Saigon and swore allegiance to newly elected President Thieu. A year later, he was named premier, a position he held until the regime’s demise.
General Khiem, along with a number of other former high-ranking South Vietnamese officers, lived in quiet retirement in San Jose. (In 2018, he was finally baptised as a Catholic there.)
The Vietnamese diaspora in America is highly factionalized, with former officers taking the most strident anti-Communist stance. General Khiem avoided controversy by maintaining a low profile and giving few interviews.