Hoon is one of South Korea's most beloved child stars. When he was only four years hold, he was picked up by the director Go Yeong-nam. He made his debut in the film The End of the World (1965) which brought in over 37 million viewers. He graduated from high school in 1982 and left the country to study abroad in Taiwan. He holds a master's degree in history. As well as Korean, he is also proficient in Chinese and English.