Boonsanong had established himself as an internationally recognized scholar in his field by the time of his return to Thailand in 1972. Back at Thammasat University in June 1972, he immediately became one of the university's leading activists. He led student demonstrations at the US Embassy in Bangkok following the Mayaguez incident. He was heavily engaged: writing papers, attending meetings, carrying out research, organizing and lecturing to hundreds of committed young people. The student movement which was to overthrow the military dictatorship in the 1973 Thai popular uprising was heating up and Thammasat was at its epicenter.