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. Currently holding the status of Winslow-Kaplan Professor of Music, he has taught at Wesleyan since 1972. 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).

Sumarsam's recent research focuses on the intersections between religion and performing arts, examining discourses of transculturalism, the performing arts, and Islam among the Javanese. 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 (2017), the International Gamelan Festival Literacy Award (2018), and Yale Institute of Sacred Music Fellowship (2019-20). He was recently named the 2018 honorary membership of the Society for Ethnomusicology.