In this interview, David Zierler, Oral Historian for AIP, interviews David Spergel, Director of the Center for Computational Astrophysics at the Flatiron Institute, and Charles Young Professor of Astronomy on the Class of 1897 Foundation, Emeritus, at Princeton. Spergel describes his transition to the Flatiron Institute and he shares that he will become the president of the Simons Foundation in summer of 2021. He explains his initial connection to Jim Simons and how the Institute differs from a traditional academic environment. Spergel describes New York City as a burgeoning center for machine learning both in academic and industrial research and he conveys his long term interest in determining the future value of machine learning to multiscale physics. He recounts his childhood on Long Island and what it was like to have a physicist for a father, and he explains his undergraduate experience in the physics program at Princeton, where Jim Peebles was a formative influence. Spergel describes his graduate work at Harvard where he worked with Bill Press on the solar neutrino problem and James Binney on orbital dynamics, and where he learned about superconducting cosmic strings. He discusses his postdoctoral appointment at the Institute for Advanced Study, where he became interested in galactic orbits and where he realized the value of the data coming out of COBE. Spergel describes his subsequent appointment to the faculty at Princeton and the promise of string theory at this time. He describes the notion of a multiverse as a non-scientific tautology and he explains why his favorite paper is Wigner’s take on the “unreasonable effectiveness of mathematics.” Spergel describes the origins of WMAP, the turning point this collaboration offered his career trajectory, and how the project allowed for pathbreaking avenues to measure the properties of the universe. He surveys the various ways that inflation, expansion, and acceleration of the universe fit with WMAP, and he explains how this collaboration is driving the next generation of experiments, and in particular, the impact in advances in detector technology. Spergel describes his involvement in the Roman Space Telescope Project and the budgeting challenges it has experienced during the Trump administration. He discusses his advocacy work in Congress on behalf of NASA. Spergel surveys his career as a teacher and a graduate mentor, and he describes how the culture of inclusivity at Princeton has improved over the years. At the end of the interview, Spergel shares his plans for the future of the Simons Foundation, he explains how he will attempt to remain close to the science, how he will use his new position to continue to promote diversity in STEM and to support cutting-edge research across a broad array of scientific endeavors.