Seton Hartnett O’Brien is a litigation associate in the New York office of Gibson, Dunn & Crutcher. She is a member of the firm’s Appellate and Constitutional Law practice group.

Her practice focuses on a broad range of high-stakes constitutional, complex commercial, appellate, and employment litigation.

Among other representative matters, Seton was a core team member in two ground-breaking victories before the United States Supreme Court. The first was The Roman Catholic Diocese of Brooklyn, New York v. Cuomo, a successful free exercise challenge to onerous State-imposed restrictions on in-person church attendance during the COVID-19 pandemic. That representation yielded a landmark Supreme Court decision that one commentator described as “one of the two most significant religion cases of the past 30 years.” The second was a successful constitutional challenge to New York State’s COVID-19 eviction moratorium brought on behalf of a group of small New York landlords and the Rent Stabilization Association of NYC, Inc. According to data published by Reuters, the Supreme Court’s decision granting an emergency injunction pending appeal in that case marked the first time the Court granted such relief to private litigants outside the religious liberties context since the inception of the pandemic, with nearly 100 prior applications having been denied.

Seton maintains an active pro bono practice where she represents immigration clients seeking protection through asylum, VAWA, or DACA. She was also the senior associate representing the American Immigration Lawyer’s Association, New Jersey Chapter, in obtaining enforcement of a settlement agreement that provides COVID-19 related protections to immigration attorneys appearing in Newark Immigration Court. Seton was awarded a Litigator of the Week Shout Out by The American Lawyer for this victory.

From 2017 to 2018, she served as law clerk to the Honorable Katharine S. Hayden of the United States District Court for the District of New Jersey. From 2018 to 2019, she served as law clerk to the Honorable Michael A. Chagares of the United States Court of Appeals for the Third Circuit.

Seton received her Juris Doctor in 2017 from Harvard Law School. She received her Bachelor of Arts degree, magna cum laude, from the College of the Holy Cross in 2014, where she was elected to Phi Beta Kappa.

She is admitted to practice in the State of New York, the State of New Jersey, the United States District Courts for the Southern and Eastern Districts of New York, the United States District Court for the District of New Jersey, and the United States Court of Appeals for the Third Circuit.