Previously, he was a mergers and acquisitions attorney at Wachtell, Lipton, Rosen & Katz. He also served as a law clerk to Justice Sonia Sotomayor on the U.S. Supreme Court. He currently serves on the boards of the Association of Marshall Scholars and Even Ground. Inc., a nonprofit that supports poverty reduction efforts in South Africa. Grinsell received his BA from Williams College, his MPhil from Oxford University as a Marshall scholar, and his JD from Yale Law School.