David R. Carpenter

DAVID CARPENTER is the head of Sidley’s West Coast Appellate practice and co-leads Sidley’s Regulatory Litigation group. David’s practice spans substantive areas of law and industries and includes: 

• Appeals and writs in federal and state appellate courts, including the United States Supreme Court and California Supreme Court.
• Acting as embedded appellate counsel at trial, working with trial counsel to prepare key motions, trial briefs, and jury instructions, and to craft strategy and preserve issues for appeal.
• Litigation challenging federal and state executive and agency actions, and local government regulatory actions.

David is a member of the California Academy of Appellate Lawyers and is ranked by Chambers USA for California Litigation: Appellate (2022–2025), with clients remarking that he “is a first-rate lawyer” (2024), “his writing is fantastic” (2023), and he has “phenomenal subject matter expertise and is very responsive” (2022). David was also recognized by The Best Lawyers in America^® for Appellate Practice and Commercial Litigation (2025). Prior to joining the firm, David clerked for the Honorable Chester J. Straub of the Court of Appeals for the Second Circuit and for the Honorable John G. Koeltl of the Southern District of New York.

Representative Appellate Matters

• Successfully argued Segal v. ASICS America Corp. (2022) in the California Supreme Court after also serving as appellate counsel for a trial that resulted in a complete defense verdict in a complex commercial dispute.
• In the products liability context, represented Johnson & Johnson in post-trial motions and on appeal, overturning a US$417 million verdict in a widely publicized case alleging that talcum powder causes ovarian cancer. David also has extensive experience representing life-science defendants in other California JCCP proceedings and in toxic tort cases.
• In the media and entertainment context, successfully represented on appeal and as appellate counsel at trial a major motion picture studio in a dispute over royalties for a musical work.
• In the consumer class action context, represented clients in the Ninth Circuit, California Court of Appeal, and trial courts across jurisdictions in cases involving pharmaceutical products, dietary supplements, and retail goods.
• In the employment context, acted as appellate counsel at trial in an alleged misclassification case that resulted in a complete defense verdict. Successfully represented clients on appeal and in defeating class certification in cases alleging failure to pay overtime, missed meal and rest breaks, and failure to reimburse, among other claims.
• Successfully represented a client in a reverse discrimination lawsuit relating to a company diversity program.
• Represented financial services companies and investment groups in complex commercial disputes, including the plaintiff in a case recognized as one of the top ten bench trial verdicts in California in 2022.
• Represented clients in bankruptcy appeals and other contested matters and adversarial proceedings in bankruptcy court.
• In the antitrust space, representing the Big 12 Conference in groundbreaking class action litigation involving name, image, and likeness monetization for student-athletes. Successfully represented a fast fashion retailer in a Ninth Circuit appeal. 

Representative Regulatory Litigation Matters

• Representing clients in challenging California’s Gas Price Gouging and Transparency Law (SB X1-2) and implementing regulations, including relating to spot-market reporting requirements.
• Advising clients on California’s Climate Accountability Laws (SB 253 and 261) relating to greenhouse-gas-emission and climate-risk reporting, including implications for out-of-state companies.
• Represented clients in litigation against the California Department of Toxic Substance Control, including obtaining a writ of mandate relating to the regulation of scrap metal recycling facilities.
• Represented a major outdoor advertiser relating to city council development agreements and Department of Transportation regulations for permit approvals.
• Represented a major refinery in litigation against a local utility.
• Advised clients regarding various other California environmental and energy matters, including Advanced Clean Fleets regulations and Truck and Bus Regulations.
• Represented a client in pre-litigation negotiations with Los Angeles County health officials over COVID-19-related conditions for re-opening.
• Experience coordinating with business and legislative-relations teams on solutions outside of litigation, and advising on various grounds for challenging state and local regulatory activity, such as First Amendment commercial speech, the California Administrative Procedure Act, and federal preemption.

• Member of the Sidley Los Angeles Committee on Associate Training and Development, for which he has developed programs on effective legal writing and research techniques.
• Member of the Litigation Executive Committee for the Los Angeles County Bar Association.
• Board member for Sound Mind Live, a nonprofit organization that seeks to reduce the stigma that surrounds mental health issues through the power of music. 

• Represented Governor Gavin Newsom in an amicus curiae brief with the U.S. Supreme Court in City of Grants Pass v. Johnson (2024), relating to cities’ ability to enforce anti-camping laws to control homeless encampments.
• Prevailed in the California Supreme Court in Doe v. Olson (2022), which held that a non-disparagement clause in a mediated settlement to resolve a Civil Harassment Restraining Order did not bar a sexual assault complainant from bringing a civil lawsuit against her alleged abuser.
• Filed an amicus brief on behalf of 82 scholars who study the transgender population in R.G. & G.R. Harris Funeral Homes, Inc. v. EEOC, 590 U.S. 140 (2020), a momentous case in which the U.S. Supreme Court held that employers are prohibited from firing employees on the basis of homosexuality or transgender status.
• Represented the Children’s Defense Fund, Fair Elections Legal Network, and the Union for Reform Judaism et al. in an amicus brief in Evenwel v. Abbott (2016), involving whether the “one-person, one-vote” principle under the Equal Protection Clause allows states to use total population, rather than voter population, when apportioning state legislative districts.
• Represented respondent in Kerry v. Din (2015), addressing the constitutional rights of a U.S. citizen to challenge the denial of a visa to her spouse.