Patrick A Costello - Dailey, LLP Attorney

Gay Parks Rainville / Attorney

Having been a co-practice leader in BigLaw, an in-house lawyer overseeing numerous important legal matters and initiatives, and co-founder of our Dailey boutique litigation firm, I have seen from all angles what it means to deliver the highest level of client service and results.

Gay Parks Rainville, one of the co-founders of Dailey LLP, litigates bet-the-company matters with the broad perspective and strategic skills that only an attorney with her decades of experience can offer. Over the course of her career, she has earned a reputation as a forthright and resourceful litigator who has honed her ability to adeptly foresee and assess her clients’ tactical options at every step of litigation.

A seasoned securities class action litigator, Gay has represented a variety of clients in securities fraud and other shareholder litigations. She has also defended various life sciences companies and consumer product manufacturers in a range of significant matters, including multi-party product liability cases, antitrust actions, and patent licensing litigations. Especially well-regarded for her written advocacy, Gay has won case-dispositive motions in a number of securities class actions and other complex cases.

Gay was honored at a recent American Bar Association, Women in Litigation Conference, as one of “100 Women Who Inspire Us.” The honorees at the event consisted of top women litigators from across the country. Gay began her legal career as women pioneers were shattering glass ceilings in law firms around the country. During her career, Gay has been a top law firm litigator (Pepper Hamilton, Harkins Cunningham), who transitioned to valued in-house counsel (Children’s Hospital of Philadelphia), and then back to the large law firm (Pepper Hamilton) as a practice group leader (co-head of Securities Litigation Group), and now she is a co-founder of Dailey LLP. Because of her journey, she knows well the importance of supporting the efforts of others. That is why service to her community is so central to Gay’s life. She is a deeply devoted supporter—and the past board chair—of SeniorLAW Center, an organization that provides free legal services to older Pennsylvanians who could not otherwise afford representation.

Prior to entering law school, Gay taught high school English and studied, coached, and performed modern dance. Nearly thirty years after earning her juris doctorate, she went back to school to earn an MFA in poetry writing. In 2021, she published her debut poetry chapbook.

Beyond Dailey

When she is not immersed in an engrossing legal brief, Gay spends as much time as possible reading and writing poetry and visiting with her extended family and lifelong friends. An avid rambler, she enjoys taking long walks while listening to British detective novels on audiobook. She also loves to travel whenever her schedule permits.

Representative Matters

  • Won case-dispositive motions in six separate federal securities class actions and one antitrust action
  • Managed the defense of numerous securities and other complex actions (cases included pharmaceutical product liability, breach of contract, insurance bad faith, consumer fraud, and antitrust, most huge and sprawling)
  • Second-chaired trial of biotech patent licensing action

Recent Speeches and Presentations


  • Named one of “100 Women Who Inspire” at the American Bar Association’s 2019 Women in Litigation Joint CLE Conference.
  • Named a Pennsylvania “Super Lawyer,” each year from 2011 to 2024; a recognition awarded to only 5% of eligible attorneys. Learn more about the selection process here.
  • Rated AV Preeminent by Martindale-Hubbell®.
  • Fellow of the American Bar Foundation.
  • Senior Fellow in the Litigation Counsel of America, a national honorary society for litigation and trial counsel.
  • Former Member and Chair of the Board of Directors (Chair: October 2013-October 2015; Board Member: 2006-2017; October 2019-2023); SeniorLAW Center Hall of Fame Inductee (March 2019).

Bar Admission

  • Pennsylvania

Federal Court Admissions

  • U.S. Court of Appeals for the Third Circuit
  • U.S. Court of Appeals for the Fourth Circuit
  • U.S. District Court for the Eastern District of Pennsylvania


  • The MFA Program for Writers at Warren Wilson College, Master of Fine Arts in Poetry Writing, 2019
  • Northwestern University School of Law, Juris Doctor, 1988
  • Northwestern University School of Education and Social Policy, Master of Arts in Teaching, 1978
  • Denison University, Bachelor of Arts in English, 1977