David Zimmer is a partner in the firm’s Litigation Department, and a member of its Appellate Litigation practice. Mr. Zimmer focuses on U.S. Supreme Court and appellate matters and complex commercial litigation, and has litigation experience in a wide range of areas, with a particular focus on intellectual property, administrative law, and consumer financial services. He has argued cases before the U.S. Supreme Court, the U.S. Courts of Appeals for the Federal, First, Second and Ninth Circuits, and the Massachusetts, New York and California appellate courts, and has drafted and contributed to briefs for cases before numerous other federal courts of appeals and district courts and state courts throughout the country. He also maintains an active pro bono practice, which focuses largely on immigration issues. Mr. Zimmer’s advocacy has been recognized by The Financial Times, The American LawyerMassachusetts Lawyers Weekly, the American Immigration Lawyers Association, and the Legal Aid Society.

Prior to joining Goodwin, Mr. Zimmer clerked for Justice Elena Kagan of the U.S. Supreme Court, and Judge William A. Fletcher of the U.S. Court of Appeals for the Ninth Circuit.

Areas of Practice
Domaines D’Expertise





Mr. Zimmer’s recent U.S. Supreme Court representations include the following:

  • Led briefing and presented oral argument before the Supreme Court in an immigration case concerning the correct interpretation of the stop-time rule for cancellation of removal. By an 8-1 vote, the Supreme Court agreed with our client, reversing the decisions of six courts of appeals, and allowing thousands of noncitizens to apply for cancellation of removal. The American Immigration Lawyers Association awarded Mr. Zimmer and his team with the Jack Wasserman Memorial Award for Excellence in Litigation based on their work on this case. Mr. Zimmer’s work on this case was also recognized by The Financial Times in its 2019 North America Innovative Lawyers Report. Pereira v. Sessions, 138 S. Ct. 2105 (2018).
  • Co-authored brief and served as second chair in the first Supreme Court case to consider the revised standards for patentability under the 2011 America Invents Act. The Court unanimously agreed with our client’s argument that an invention is “on sale” for purposes of the statute if it is sold or offered for sale, and that it does not matter whether the sales are public or make the invention “available to the public” more broadly. Helsinn Healthcare S.A. v. Teva Pharm. USA, Inc., 139 S. Ct. 628 (2019).
  • On behalf of a major banking client, co-authored the petition for certiorari and merits briefs that persuaded the Supreme Court to grant certiorari to resolve questions about the scope of the Fair Housing Act, adopt our client’s argument, and set aside the appellate decision applying a relaxed causation standard.

His other significant representations include the following:

  • Led briefing and presented oral argument that successfully convinced the First Circuit to hold that our client’s sustained overdraft fees do not qualify as “interest” under regulations implementing the National Bank Act. The court’s decision was the first appellate decision addressing the proper classification of sustained overdraft fees. Fawcett v. Citizens Bank, N.A., 919 F.3d 133 (1st Cir. 2019). 
  • Developed appellate strategy and co-authored briefs that convinced the Federal Circuit to reverse the district court’s factual findings as clearly erroneous, and hold that the patent asserted against our client was invalid as obvious. The Federal Circuit’s decision cleared the path for our client to launch its generic pharmaceutical product. Bayer Pharma AG v. Watson Laboratories, Inc., 874 F.3d 1316 (Fed. Cir. 2017). 
  • Co-authored winning briefs in a significant appeal in the Federal Circuit about the scope of “covered business method” review of patents by the Patent Trial and Appeal Board. Managing IP named the case one of 2016’s “Milestone Cases.” Unwired Planet, LLC v. Google Inc., 841 F.3d 1376 (Fed. Cir. 2016).
  • Appointed by Massachusetts Attorney General Maura Healey to serve as Special Assistant Attorney General in order to represent District Attorneys Marian Ryan and Rachael Rollins in their ongoing challenge to ICE’s policy of conducting civil immigration arrests at Massachusetts state courthouses. In 2019, The American Lawyer recognized Mr. Zimmer as a Litigator of the Week nominee for his groundbreaking work on this case.
  • On behalf of a major mortgage lender, co-authored briefs persuading a California trial judge to grant judgment notwithstanding the verdict on a multimillion-dollar tort judgment against our client, and appellate briefs persuading the California Court of Appeal to affirm the trial court’s decision and the California Supreme Court to deny review.
  • On behalf of four nationwide mortgage lenders, co-authored briefs persuading the Ninth Circuit to dismiss a False Claims Act lawsuit demanding a multibillion-dollar recovery.
  • Successfully briefed and argued cases before the Second and Ninth Circuits on behalf of pro bono clients, convincing the courts to grant petitions for review from decisions of the Board of Immigration Appeals finding our clients removable. The Legal Aid Society recognized Mr. Zimmer for this work by awarding him its Pro Bono Publico Award.
Professional Activities

In addition to his work at Goodwin, Mr. Zimmer currently serves as a Lecturer at Harvard Law School and as the Director of its Federal Courts Clinic. He also serves on the Board of Directors for both the ACLU of Massachusetts and Lawyers for Civil Rights; is a member of the Emerging Leaders Council of the Legal Services Corporation; and is on the Amicus Committee of the American Immigration Lawyers Association.

Prior to joining Goodwin, Mr. Zimmer served as a law clerk to Justice Elena Kagan of the Supreme Court of the United States, and Judge William A. Fletcher of the U.S. Court of Appeals for the Ninth Circuit. He also previously worked as an associate at Keker & Van Nest.


While attending law school, Mr. Zimmer was an Articles Editor and the Forum Chair for the Harvard Law Review.

In The News









J.D., 2010
Harvard Law School
(magna cum laude)
M.P.A/I.D., 2010
Harvard Kennedy School of Government
B.A., 2004
Harvard College
(magna cum laude)


2012 to 2013 U.S. Supreme Court, Honorable Elena Kagan
2010 to 2011 U.S. Court of Appeals for the Ninth Circuit, Honorable William A. Fletcher





U.S. Supreme Court
U.S. Court of Appeals for the District of Columbia Circuit
U.S. Court of Appeals for the First Circuit
U.S. Court of Appeals for the Second Circuit
U.S. Court of Appeals for the Fifth Circuit
U.S. Court of Appeals for the Ninth Circuit
U.S. Court of Appeals for the Federal Circuit
U.S. District Court for the Northern District of California
U.S. District Court for the Central District of California
U.S. District Court for the District of Massachusetts
U.S. Court of Federal Claims
U.S. Tax Court
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Our clients rely on us for world-class advisory services, counsel on complex transactional work and high-stakes litigation. Specializing in matters involving the financial, life sciences, private equity, real estate, and technology industries, we use a collaborative, cross-disciplinary approach to resolve our clients’ most challenging issues. To find out more, please contact us.

Unsere Kunden verlassen sich auf unsere erstklassige Beratung, vor allem im Hinblick auf komplexe Transaktionen und High-Stakes-Prozesse. Spezialisiert auf Angelegenheiten der Finanz-, Life-Sciences-, Private-Equity-, Immobilien-und Technologie-Branchen, verwenden wir einen kooperativen und interdisziplinären Ansatz, um Fragen unserer Kunden auch in extremen Spezialsituationen einer Lösung zuzuführen. Sie wollen mehr erfahren? Kontaktieren Sie uns gerne.

Nos équipes interviennent aux côtés de nos clients, industriels, fonds d’investissement, startups, institutions financières et dirigeants, dans le cadre de transactions et de contentieux complexes, et apportent des conseils de tout premier plan dans les secteurs financiers, des Sciences de la Vie, du Private Equity, de l’immobilier et des technologies. Nous traitons les dossiers juridiques de manière intègre, ingénieuse, souple et audacieuse pour répondre efficacement aux enjeux propres à chacun de nos clients, quels que soient la taille de l’opération et le secteur d’activité. Pour en savoir plus, contactez-nous.


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