Jeff Gewirtz is the Executive Vice President of Business Affairs and Chief Legal Officer for Brooklyn Sports & Entertainment (BSE). Gewirtz joined the Brooklyn Nets and its affiliated arena operating company in May 2007 as Senior Vice President and General Counsel and he was promoted to his current position in 2010.

Gewirtz oversees legal and business affairs for the Nets, Barclays Center, the business operations of the New York Islanders, and Nassau Veterans Memorial Coliseum. Gewirtz is also responsible for interfacing with the NBA on a wide range of transactional and compliance matters. In addition, he oversees the human resources function for all of the Brooklyn Sports & Entertainment companies.

Prior to the Nets, Gewirtz served as the United States Olympic Committee (USOC) General Counsel and Chief Legal & Government Affairs Officer where he was responsible for all USOC legal matters, as well as the USOC's government relations activities with Congress and federal government agencies.

Before he joined the USOC, Gewirtz was Counsel - sports & entertainment transactions, marketing and media in The Coca-Cola Company's Corporate Legal Division, where he negotiated many of Coca-Cola's most significant sports marketing and media transactions, including its $500 million+ NCAA Corporate Champion marketing and media alliance with CBS Sports. In 2005, as a secondment, Gewirtz served as Counsel for Coca-Cola’s Southeast and West Asia Division, based in Bangkok, Thailand. Prior to Coca-Cola, Gewirtz was Director of Legal Affairs for IOC Television & Marketing Services SA, based in Lausanne, Switzerland, where he was a primary negotiator of global Olympic sponsorship, technology, and media alliances for the International Olympic Committee and for the Salt Lake and Athens Olympic Organizing Committee, respectively. He has also served as General Counsel for the LPGA TOUR and as Manager of Tournament & Business Affairs with the WTA. Gewirtz began his legal career as an associate with the New York City law firm of Dunnington, Bartholow & Miller, LLP, where he served as the associate to the General Counsel of the United States Tennis Association (USTA) and worked within the firm's Corporate and Advertising Industry legal groups. In addition, he previously served as pro bono General Counsel of the USTA's Eastern Section. 

Gewirtz was named 2014 Sports Counsel of the Year by the Association of Media & Entertainment Counsel and his current legal department was named one of the top 50 in-house legal departments in the United States under the GC Powerlist for 2015, published by The Legal 500 Series. In 2009 Gewirtz was selected to the prestigious "Forty Under 40" by Sports Business Journal as one of the 40 top sports executives under the age of 40 in the United States. In addition, in 2003 he was named to the annual list of "Georgia Lawyers on the Rise" by Fulton County Daily Report, Atlanta's legal newspaper of record. 

Gewirtz was formerly on the faculty of Brooklyn Law School and New York Law School, serving as an adjunct professor of sports law at both schools and he is currently on the adjunct faculty of the Madrid, Spain-based Instituto Superior de Derecho y Economia for its US-based masters program in global sports law, which is associated with Columbia University's graduate sports management program. He is the immediate-past Chair of the Sports Division and currently sits on the Governing Committee of the American Bar Association's Forum on the Entertainment and Sports Industries, he sits on the Board of Directors of both the National Sports Law Institute and the Sports Lawyers Association, and he is a Board of Editors member of both the Journal of International Media & Entertainment Law and Professional Sports and the Law. Gewirtz has lectured extensively, both in the United States and internationally, on a variety of commercial legal and business issues in sport, including before groups such as the Association of National Olympic Committees of Africa, the Australia and New Zealand Sports Law Association, the British Association for Sport and Law, the Oceania National Olympic Committees, and at the 2003 SportAccord International Convention in Madrid, Spain. 

In June 2010 Gewirtz was appointed to the Board of Trustees of Jewish Vocational Services of MetroWest New Jersey and was a former Executive Committee member of the UJA-Federation of New York Sports for Youth Initiative.

A native of Baldwin Harbor, New York, Gewirtz is a graduate of Tufts University, where he was a four-year member and 1990-91 Captain of the Tufts Varsity Tennis Team, as well as a member of its 1989 New England Championship team. In 2016 he was appointed to the Tufts Athletics Board of Advisors. Gewirtz received his law degree from Brooklyn Law School, where he was the recipient of a three-year merit scholarship and from which he is a two-time recipient of its Alumni Achievement Award in Sports Law. As a junior tennis player, Gewirtz held the #1 Doubles Ranking in the USTA's Eastern Section and he also held the #1 singles ranking in the Long Island District of the Eastern Section.

Gewirtz and his wife, Brooke Raphael, who is a project manager at Celgene Corporation, reside in Manhattan. They are expecting their first child.