Shannon D. SweeneyShareholder

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Shannon D. Sweeney is part of Sullivan Hill’s Commercial and Business Litigation, Real Estate, Construction, and Employment Law practice groups. She has substantial experience in complex corporate litigation, large commercial disputes, and consumer and securities fraud class action lawsuits in both state and federal courts.

Ms. Sweeney also has significant appellate experience in California state and federal courts, including successfully arguing at the United States Court of Appeals for the Ninth Circuit, as well as first and second-chair trial experience. She is a persuasive oral advocate, and has also enjoyed a very successful motion practice. Ms. Sweeney was selected by her peers for inclusion in the 27th, 28th, 29th and 30th edition of Best Lawyers in America® in the field of Commercial Litigation. She also has been selected for the “Women of Influence” award by San Diego Metropolitan Magazine 2020. Ms. Sweeney was also recognized in the special section titled, “Women of Influence in Law 2021,” of the San Diego Business Journal (SDBJ) for her accomplishments in the San Diego legal community.

Ms. Sweeney obtained her J.D. from the University of San Francisco School of Law in 1999, where she was an active member of the Moot Court Board and the USF Law Review (with published case note: Sharon P. v. Arman). She was the winner of the McFetridge Award for best trial advocate, and finalist for the Advocate of the Year Competition.  She was also a member of the National Moot Court and Appellate Advocacy Competitions Teams.

Ms. Sweeney was admitted to the State Bar of California in 1999, the State Bar of Texas in 2007, and the State Bar of New York in 2008. Additionally, she is admitted to practice before all courts of the State of California and the United States District Court for the Southern, Central, Eastern and Northern Districts of California, and the United States Court of Appeals for the Ninth Circuit.


  • University of San Francisco School of Law, J.D., 1999
  • Scripps College, B.A., 1992


Ms. Sweeney has successfully defended numerous publicly-traded and large companies, in consumer and products liability class actions, securities litigation, and pharma/biotech litigation. She has also assisted individuals and companies in employment, contractual and management disputes, as well as overseen internal investigations. As a long-time advocate for gender equality, Ms. Sweeney especially enjoys representing women-owned and women-led businesses.

Representative Matters:

Class Actions

  • Burghardt v. Nutronics Labs, Inc.: Successfully negotiated the dismissal of the putative California class action in the Southern District of California.
  • Burns v. WD-40 Company: Successfully resolved by summary judgment and motion to dismiss a putative products liability nationwide and California class action in Orange County Superior Court; defeated the appeal, including arguing the case in the Fourth District.
  • Drimmer v. WD-40 Company: Successfully defeated class certification in a federal putative products liability nationwide and California class action; defeated the appeal brought by the putative class, including arguing the case in the Ninth Circuit.
  • Engler v. Breg, Inc. et al.: Successfully managed a litigation team’s efforts to defeat class certification in a putative worldwide and California class action in San Diego Superior Court.
  • Valentine v. WD-40 Company: By summary judgment, successfully resolved a putative products liability nationwide class in San Diego Superior Court; defeated the appeal brought by the putative class.
  • Worrall et al. v. Pedernales Electric Cooperative et al.: On behalf of plaintiffs, assisted in settling a high-profile putative class action brought against the largest electrical cooperative in the United States in the District Court of Travis County, Texas (affirmed on appeal); information obtained by plaintiffs in discovery was the subject of hearings before the U.S. House of Representatives seeking nationwide reforms.
  • Ahern Rentals, Inc.: Managed the defense of several federal and California state class actions.
  • Martin v. Maxim Pharmaceuticals, Inc. et al.: In several successive winning motions to dismiss, assisted in the defeat of a federal securities class action brought when Maxim’s stock dropped after it failed to obtain certain FDA approvals.
  • In re Gateway, Inc. Securities Litigation: At the motion to dismiss stage, assisted in the defeat of a federal securities class action brought when Gateway failed to meet its projections.

Other Complex Litigation:

  • Responsible for primary management of a major SEC investigation of a large publicly traded company (client confidential).
  • Responsible for primary management of a substantial Special Litigation Committee investigation of a publicly traded company (client confidential).
  • Hilkene v. WD-40 Company: Convinced plaintiff to voluntarily dismiss a federal securities fraud case with prejudice at the close of discovery.
  • Grynberg v. Shell Exploration B.V. et al.: At the summary judgment stage, assisted in the dismissal of a multi-billion dollar case brought against Shell (affirmed by the Tenth Circuit).
  • Danisco USA Inc.: Successfully settled a product liability case brought against one of the world’s largest suppliers of food ingredients.
  • Responsible for preparing the litigation strategy for, and day-to-day management of, a successful challenge to a 1000-page environmental impact report supporting a significant housing development in San Diego County client confidential.


Ms. Sweeney is a member of the State Bar of California, San Diego County Bar Association and Lawyers Club of San Diego. She currently serves as the President of the MOXIE Theatre Board of Directors, a professional non-profit theatre in San Diego with a mission to create more diverse and honest images of women. She has also been honored to share her legal expertise by serving as Program Director and teaching trial skills and deposition courses throughout the country for the National Institute of Trial Advocacy for nearly 20 years.