Jonathan Hammill graduated from the Juilliard School in New York. His primary teachers include Carolyn Wahl, Julie Landsman and Dale Clevenger. He attended the Pacific Music Festival in Sapporo, Japan, three times between 1999 and 2001. In 1999, he was a member of the Civic Orchestra of Chicago and has played with orchestras such as the Chicago, London, New Jersey, NHK Symphony Orchestras and the Florida Orchestra. In 2001, he joined the Tokyo Symphony Orchestra as principal horn and he still holds this post today.

Jonathan teaches at The British School in Tokyo, Dolce Music Academy, and Senzoku Gakuen College of Music. He is also a member of the Tsunobue Horn Ensemble.