Currently holding the status of Winslow-Kaplan Professor of Music, Sumarsam has taught Javanese gamelan at Wesleyan since 1972, and a course on music and theater of Indonesia since 1990s. His research on the history, theory, and performance practice of gamelan and wayang, and on Indonesia-Western encounter theme has resulted the publication of numerous articles and two books: Gamelan: Cultural Interaction and Musical Development in Central Java (1995) and Javanese Gamelan and the West (2013), and a forthcoming, The In-Between in Javanese Performing Arts: History and Myth, Interculturalism and Interreligiosity (October 1, 2024). Recently, Sumarsam embarks in a new research on hybrid musical drama in cultural-border crossing.

Sumarsam has played Javanese gamelan since childhood. He is also a keen amateur dhalang (puppeteer) of wayang puppet play. He holds a BA degree from Akademi Seni Karawitan Indonesia, MA from Wesleyan, and PhD from Cornell. He is the recipient of a number of fellowship grants and awards, including the National Endowment for the Humanities and the American Council of Learned Societies fellowship (2016-17), Indonesian Bintang Satyalencana Cultural Award from the President of Indonesia (2017), and Yale Institute of Sacred Music Fellowship (2019-20). He was recently named the 2018 honorary membership of the Society for Ethnomusicology.