This wide-ranging interview explores the career of Jim Decker, most of which has been at the U.S. Department of Energy and its predecessor agencies. Decker first worked in the fusion energy program, and from 1985 to 2007 he was Principal Deputy Director of the DOE Office of Energy Research, which was renamed the Office of Science in 1998. The position was the highest-level career position within the office. The interview covers the evolving fortunes of fusion research in the U.S., including expanding support in the 1970s, U.S. participation in the international ITER project, and deep funding cuts in the 1990s. The leadership of Al Trivelpiece at the office, the development of DOEs high-performance computing efforts, and the management of the Superconducting Super Collider project are discussed in some detail. Other subjects include the origins of DOEs support for the Human Genome Project, the development of DOEs procedures for oversight of major projects, recent trends toward funding centers and special initiatives, the evolving status of the Office of Science within DOE, and Deckers experiences with Congress and successive presidential administrations.