Michael Cassidy is the Managing Attorney of the Plattsburgh Office of Prisoners' Legal Services of New York (PLS), as well as the statewide PLS Litigation Coordinator. He has litigated and supervised numerous prison cases in both state and federal courts. These have included cases involving excessive force, as well as deliberate indifference claims involving failure to protect and denial of medical care. He has also litigated and handled exhaustion issues under the PLRA, religious rights claims, retaliation claims, and various types of challenges to solitary confinement, including many state and federal procedural due process claims involving prison disciplinary issues.

He received his Juris doctor, cum laude, from Vermont Law School in 1991 and his B.A. in Political Science from the University of Vermont in 1987. He served as a staff attorney at PLS from 1991-1996 and Managing Attorney for Litigation from 1996-1998. He engaged in private practice in Burlington, Vermont and Portland, Maine from 1998-2002, before returning to the PLS as the Plattsburgh Office Managing Attorney. Since 2017 he has also served as the statewide Litigation Coordinator for PLS, which has offices in Albany, Ithaca, Buffalo, and Plattsburgh.

He is admitted to the state bars of New York, Vermont and Maine. He is also admitted to practice in the United States District Courts for the District of Vermont, the District of Maine, the Northern District of New York, and the Western District of New York, as well as the United States Courts of Appeals for the First, Second, and D.C. Circuits.