In this interview, David Zierler, Oral Historian for AIP, interviews Robert Sugar, emeritus professor and research professor of physics at UC Santa Barbara. Sugar recounts his childhood in New York and Ohio, and he describes his developing interest in physics in high school. He discusses his undergraduate education at Harvard, his early decision to focus on theory and his decision to go to Princeton for his Ph.D. Sugar describes his longtime collaboration and friendship with his graduate advisor Dick Blankenbecler, and his graduate research on phase shifts that appeared in scattering amplitudes. He discusses his postdoctoral research at Columbia, and his decision to accept a faculty position at UCSB. Sugar describes his contributions in building up the physics department into a major center of research, and he discusses his interest in Regge theory and the behavior in in the angular momentum plane. He discusses the development of the Kavli Institute and his growing interest in lattice gauge theory and describes its relationship to QCD. Sugar describes his collaborative work on MILC and explains how computational power has consistently lagged behind his theoretical interests. He explains how the priorities of the DOE and the NSF with regard to supporting physics has changed over the decades, and at the end of the interview, he discusses his long-term collaboration with Fermilab and his contributions as a mentor to young physicists.