FacultyFaculty/Author Profile
Marc J. Zwillinger

Marc J. Zwillinger

Zwillinger Genetski LLP

Washington, DC, USA

Marc Zwillinger is the founder and managing member of ZwillGen PLLC. Marc counsels on issues related to the laws governing Internet practices, including issues related to the Electronic Communications Privacy Act (“ECPA”), the Foreign Intelligence Surveillance Act (“FISA”), data breach notification, data privacy, and fantasy sports. He also helps Internet Service Providers and other clients with their compliance obligations pertaining to the use and disclosure of customer and subscriber information.

Marc also works with clients who have suffered security breaches in managing the incident response, conducting internal investigations, complying with security breach notification laws, and responding to FTC and state Attorney General inquiries.

In 2008 Marc made history by representing Yahoo! in its 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. Since then he has continued working on national security and foreign intelligence matters and holds a Top Secret security clearance.

Over the past two years, Marc has represented Internet clients in seven FTC investigations involving data security, data privacy, and advertising practices. He has negotiated settlement agreements with the NY & MD state Attorney General offices, and defended media and Internet companies against privacy class actions brought under ECPA, CFAA, the VPPA and the VRPA.

In both the Chambers USA and Chambers Global guides, Marc is listed as  a leader in the field of Privacy and Data Security law. Prior to founding ZwillGen PLLC, Marc ran the Privacy and Security groups at 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.

Since 2004, Marc has briefed and argued appellate cases before the Court of Appeals for the 1st, 3rd, 5th 7th, 9th, and 11th Circuit Court as well as the Foreign Intelligence Surveillance Courts.

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.


Harvard Law, J.D., 1994, magna cum laude

Tufts University, B.A., 1991, magna cum laude

Prior Experience

Sonnenschein Nath and Rosenthal LLP

Kirkland & Ellis LLP

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

Admitted to Bar


District of Columbia


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