DANIEL HAY represents individuals and corporations in all stages of complex and high-stakes litigation, including critical motions practice, oral argument, discovery, trial, and appeal. Daniel has extensive experience in both commercial disputes and government-facing litigation, including in matters defending against government enforcement actions and challenging federal regulatory actions under the Administrative Procedure Act.

Daniel J. Hay
- Commercial Litigation and Disputes
- Supreme Court and Appellate
- White Collar: Government Litigation and Investigations
Experience
- Representative Matters
- Pro Bono
Daniel has argued and authored briefs on behalf of clients in the U.S. Supreme Court and federal and state courts of appeals. Daniel’s recent appellate victories include:
- NCFA v. Blinken, 4 F.4th 106 (D.C. Cir. 2021): Successfully argued and briefed a challenge to agency guidance documents, which the D.C. Circuit unanimously vacated on the grounds that the guidance imposed new legislative rules without notice and comment. Daniel also persuaded the D.C. Circuit to reverse the district court’s ruling that our client lacked associational standing.
- NYSDEC v. FERC, 991 F.3d 439 (2d Cir. 2021), and National Fuel Gas Supply Corp. v. NYSDEC, 761 F. App’x 68 (2d Cir. 2019): Successfully represented an energy company in a pair of petitions for review concerning our client’s authority to construct a federally approved natural gas pipeline. Law360 awarded the Sidley team its “Legal Lion of the Week” title for this victory.
- New Hampshire Lottery Commission v. Rosen, 986 F.3d 39 (1st Cir. 2021): Amicus counsel to the nation’s largest lottery and gaming company in a successful challenge to an OLC opinion interpreting the Wire Act to reach non-sports betting.
- Rios v. Bayer Corp., --- N.E.3d --- (Ill. 2020): Successfully represented a major medical device manufacturer in a case holding that a state court lacks personal jurisdiction over products liability claims brought by plaintiffs who neither reside in nor allege to have been injured in the forum state.
- United States of America v. AT&T, 916 F.3d 1029 (D.C. Cir. 2019): Successfully represented AT&T in the government’s appeal of the district court decision allowing AT&T to merge with Time Warner. The Wall Street Journal described this decision as “cement[ing] one of the biggest losses for the Justice Department’s antitrust division in a generation.”
- Murphy v. NCAA, 138 S. Ct. 1461 (2018): Amicus counsel to the American Gaming Association in support of a successful constitutional challenge to a federal law that prohibited states from making their own policy on whether to regulate sports betting.
Daniel also has experience at all stages of trial representation, from pre-litigation counseling and dispositive motions practice through discovery and trial. Daniel’s current and recent trial representations include:
- Representing a national outdoor advertising company in a complex Takings, First Amendment, and breach of contract challenge to a local government ordinance.
- Representing a major multinational technology company indicted in federal court on charges of racketeering, trade secret theft, bank fraud, and other alleged offenses.
- Member of a trial team representing a Fortune 500 financial services company in a deceptive advertising and unfair business practices case brought by the Federal Trade Commission.
- Represented a global pharmaceutical manufacturer in a multifaceted Lanham Act case in the U.S. District Court for the Northern District of California, the U.S. Court of Appeals for the Ninth Circuit, and the Judicial Panel on Multidistrict Litigation.
- Obtained a writ of mandamus quashing a state trial court’s order requiring Sidley’s client to produce a privileged and highly confidential report of an outside counsel investigation.
- Successfully represented a Luxembourg-based holding company in obtaining dismissal of a multibillion-dollar fraud and breach of contract complaint in the New York Supreme Court, Commercial Division.
Daniel joined Sidley following a clerkship with Judge Steven Colloton of the U.S. Court of Appeals for the Eighth Circuit. Prior to his clerkship, Daniel completed a D.C. Bar Association Pro Bono Fellowship at the Becket Fund for Religious Liberty, where he represented religious nonprofits in constitutional cases before the federal courts of appeals.
Daniel received his law degree from Vanderbilt University Law School, where he was a John W. Wade Scholar and served as editor in chief of the Vanderbilt Law Review. Before attending law school, Daniel worked as a middle school math teacher with Teach for America and an aide to a member of Congress.
Daniel maintains an active pro bono practice on behalf of nonprofits, religious organizations, and civil rights. Daniel’s recent pro bono victories include:
- Obtained compassionate release on behalf of a federal prisoner whose underlying health conditions placed him at serious risk from COVID-19.
- As court-appointed counsel, convinced the Sixth Circuit to reinstate a federal civil rights lawsuit alleging a violation of a prisoner’s religious liberties.
- Part of a trial team that secured a jury award of compensatory and punitive damages in a federal civil rights case alleging unconstitutionally excessive force in effecting arrest.
Daniel is also president of the board of directors of the Hemophilia Association of the Capital Area.
Capabilities
- Commercial Litigation and Disputes
- Supreme Court and Appellate
- White Collar: Government Litigation and Investigations
- Administrative Law Appeals
- Alternative Dispute Resolution
- Antitrust and Unfair Competition
- Antitrust Litigation
- APA Litigation & Regulatory Strategy in the Pre-Litigation Phase
- Business Torts
- Commercial Litigation Appeals
- Contract Litigation
- Educational Institutions
- Energy and Transportation Law Appeals
- First Amendment Law
- Medtech and Medical Devices: Healthcare, Patent Litigation, and Product Liability
- Multidistrict Litigation
- Patent and Intellectual Property Rights Appeals
- Preemption
- Pro Bono Appeals
- Products Liability and Class Actions Appeals
- Sports
- Trial Litigation
News & Insights
Credentials
Admissions & Certifications
- U.S. Court of Appeals, 1st Circuit
- U.S. Court of Appeals, 2nd Circuit
- U.S. Court of Appeals, 6th Circuit
- U.S. Court of Appeals, 8th Circuit
- U.S. Court of Appeals, 9th Circuit
- U.S. Court of Appeals, 10th Circuit
- U.S. Court of Appeals, D.C. Circuit
- U.S. Court of Appeals, Federal Circuit
- U.S. District Court, District of Columbia
- U.S. District Court, S.D. of New York
- District of Columbia
- New York
Education
- Vanderbilt University Law School, J.D., 2015 (John W. Wade Scholar, Order of the Coif, Editor-in-Chief, Vanderbilt Law Review)
- Wilmington University, M.A., 2011
- The King's College, B.A., 2010 (magna cum laude)
Clerkships
- Steven M. Colloton, U.S. Court of Appeals, 8th Circuit (2015 - 2016)