This article memorializes Donald N. Bersoff (1939-2024), who provided a foundational influence on the development of American law-psychology and served as the 2013 president of the American Psychological Association (APA). Don had a long and meaningful career as a psychologist and a lawyer. One of Don's greatest interests was in training psychologist-lawyers who would make meaningful contributions to either field. After a decade as APA general counsel, he was recruited to direct the law-psychology program at Hahnemann University and Villanova School of Law. He was elected as the president of the APA in 2013; two of the major themes of his presidency involved encouraging service to military veterans and their families, and promoting diversity within the ranks of psychology to better serve an increasingly diverse population. (PsycInfo Database Record (c) 2024 APA, all rights reserved).