 He is a member of the American Bar Association, the New York City Bar Association (Chair, Communications Law Committee, 1986–89), and the American Judicature Society.He is a Fellow of the American Bar Foundation.Judge Sack is an Adviser, American Law Institute's Restatement Third of Torts, Defamation and Privacy, 2019– ; and an Adviser to the "Global Media Freedom Initiative's High-Level Panel of Legal Experts" convened at the request of the UK and Canadian governments, 2019– .