Haing Somnang Ngor was born in Samrong Young (in 1940, French Indochina), Bati district, now Takeo province, Cambodia, he trained as a surgeon and gynecologist. He was practicing in the capital, Phnom Penh, in 1975 when Pol Pot’s Khmer Rouge seized control of the country and proclaimed it Democratic Kampuchea. He was compelled to conceal his education, medical skills, and even the fact that he wore glasses to avoid the new regime’s intense hostility to intellectuals and professionals. After the fall of the Khmer Rouge in 1979, Ngor worked as a doctor in a refugee camp in Thailand and left with his niece for the United States on August 30, 1980.

Ngor, despite having no previous acting experience, was cast as Dith Pran in The Killing Fields (1984), a role for which he won (among many honors) the Academy Award for Best Supporting Actor, becoming the first Asian to win Best Supporting Actor in debut performance, the second Asian actor to ever win an Oscar, and one of two amateur actors to win an Oscar. 

Ngor went on to appear in various other onscreen projects, most memorably in the Vanishing Son miniseries and Oliver Stone’s Heaven & Earth (1993). He also appeared in the Hong Kong film Eastern Condors (1987), which was directed by and starred Sammo Hung.

According to Wikipedia