With the country taken over by the Khmer Rouge in 1975, Pung fled to neighbouring Thailand to seek refuge in a Thai refugee camp.

After leaving the camp in 1980, Pung soon secured a job as a salesman and later became a goldsmith in Montreal, Canada where he would spend the next eleven years of his life until his return to Cambodia in the early 1990s.

Pung started his career as a goldsmith operating from a small kiosk in a grocery shop in Montreal, Canada's Chinatown.

[1] With a diversified business interest, Pung's venture into non-financial services and solutions led to the creation of one of Cambodia's largest investment and development companies with various property development projects such as Sorya Shopping Center, Cambodia's first ever mall, Canadia Tower, the Kingdom's first skyscraper, Koh Pich, Chroy Changvar Satellite City, the 2,600 hectare Techo International Airport slated to become one of the world's largest airports.

[4] Since 2020, Dr. Pung's OCIC Group and its affiliates has invested an estimated US$5 billion in numerous public and social infrastructure projects throughout Cambodia with more projects in works such as Norea City, the Kong Sam Ol Overpass,[5] the Russey Keo Bridge and Russey Keo Flyover, the Koh Norea Bridge[6] and more to come.