A former law clerk to U.S. Supreme Court Justice John M. Harlan (1959), Lesnick has served since 1978 as Impartial Umpire under the AFL-CIO Internal Disputes Plan. He is a founder and past president of the Society of American Law Teachers and has participated in litigation, training, and consultative work related to the legal problems of poor people. He has worked to develop methods by which law students, teachers, and practitioners can integrate their work with their aspirations and values, and was the 2030 recipient of an AALS Award for outstanding contributions to public service.