Marc Zwillinger

Founder and Managing Member, Washington, D.C.

Marc Zwillinger is the founder and managing member of ZwillGen PLLC and regularly provides advice and counsel on issues related to the increasingly complex laws governing Internet practices, including issues related to Electronic Communications Privacy Act (“ECPA”), the Wiretap and Communication Acts, privacy, CAN-SPAM, FISA, Internet gambling and adult-oriented content.  He also helps Internet Service Providers and other clients comply with their compliance obligations pertaining to the use and disclosure of customer and subscriber information. 

Marc also provides corporations with advice and counsel on protecting the data on their networks from internal and external threats, and counsels them through handling data breaches and internal misuse of their network.  Marc works with clients who have suffered security breaches in conducting internal investigations, complying with security breach notification laws, and responding to FTC and state Attorney General inquiries.

In 2008 Marc represented Yahoo! in its now unsealed litigation with the government over the government's effort to force Yahoo! to comply with Directives issued under the Protect America Act, the precursor to the FISA Amendments Act. In that case, he appeared before the Foreign Intelligence Surveillance Court of Review, and is believed to be the only private lawyer ever to do so. 

The 2010 through 2014 client’s guides of Chambers USA: America’s Leading Lawyers for Business recognizes him as a leader in Privacy & Data Security law, noting specifically his expertise with ECPA and FISA issues. 

Prior to starting ZwillGen PLLC, Marc ran the Privacy and Security groups at two major national firms: Sonnenschein Nath and Rosenthal LLP and Kirkland & Ellis LLP.  Before that, he spent three years prosecuting cybercrime from the Computer Crime and Intellectual Property Section of the Criminal Division of the Department of Justice. 

After receiving his J.D. from Harvard Law School, magna cum laude in 1994, Marc clerked for Judge Mark L. Wolf of the United States District Court, District of Massachusetts.  

Marc frequently is invited to testify before congress, speak to various professional audiences and to conduct in-house training courses. He has appeared on national news programs including CNN's The Situation Room, ABC's World News Tonight, Good Morning America, C-Span's Washington Journal, and other programs. He is also an adjunct professor of Cybercrime at the Georgetown University Law Center in Washington, D.C.  Marc holds an active security clearance for classified matters. In 2013, Marc was appointed the new chair of the D.C. Bar Practice Management Service Committee.

Marc Zwillinger


Harvard Law, J.D., Magna Cum Laude, 1994

Tufts University, B.A., Magna Cum Laude 1991

Prior Experience

Sonnenschein Nath and Rosenthal LLP --Chair of Privacy and Security Group

Kirkland & Ellis LLP

Department of Justice --Computer Crime and Intellectual Property Section of the Criminal Division

Court Admissions

United States Supreme Court

United States Court of Appeals  for the 1st, 3rd, 4th, 5th, 7th, 9th and 11th Circuits 

United States District Court for the Northern District of Illinois

D.C. Court of Appeals

Illinois Supreme Court

Admitted to Bar

Illinois, 1994

District of Columbia, 1995