Over a distinguished career, Regents Professor Karsten Schwan has made significant contributions across a diverse array of topics in computer systems, including operating systems for multi-core platforms, virtualization technologies, enterprise middleware, and high-performance computing. In this paper, we summarize his legacy of key research contributions in general-purpose GPU computing. His vision encompassed the conceptualization, implementation, and demonstration of systems abstractions and runtime methods to elevate GPUs into first-class citizens in today's and future heterogeneous computing environments. To this end, his contributions include novel scheduling and resource management abstractions, runtime specialization, and novel data management techniques to support scalable, distributed GPU frameworks.