Born in Lopburi, Thailand, Soonponsri graduated from Silpakorn University in 1962, and completed a Master of Fine Arts in sculpture and painting at the Otis Art Institute, Los Angeles in 1971. Throughout his career he has pushed the boundaries of institutional convention. While abstraction was popular with younger Thai artists such as Soonponsri in the 1960s, the National Exhibition of Art and Silpakorn University still favored more traditional works and approaches. Breakaway exhibitions arose, and Soonponsri was involved in one of the early shows held at the privately owned Bangkapi Gallery in 1964. He took on a politically active role following the pro-democracy student protests of 1973. Soonponsri became chairman of the Artists’ Front of Thailand, founded in 1974 with the aim of harnessing art in the quest to obtain democratic government. He was an organizer of the first Open Art Exhibition of Thailand, held in 1979 as a further challenge to the National Exhibition of Art. His activism contributed to significant change, and he later became a jury member for a revitalized National Art Exhibition. Soonponsri’s works are abstracted and emotive. In the early 1990s he was a lecturer at Silpakorn University with other well-known artists such as Ithipol Thangchalok.