Mark D. Cohen served as a Judge of the New York State Court of Claims from 2006 to 2020. During that period, he was an Acting New York State Supreme Court Justice in Suffolk County, New York and from 2015 to 2020, was the Supervising Judge of the Superior Criminal Courts for the Tenth Judicial District (Suffolk). Judge Cohen is of counsel to the Hauppauge, New York law firm of .LaPinta, Lesko, & Miskiewicz, PC.

Judge Cohen has been an adjunct law professor at the Touro Law Center in Central Islip, New York since 1993. In 2021, he was appointed by the law school as its Distinguished Jurist in Residence, and in 2025, was presented with the law center’s Builder’s Award. Touro honored him in 2004 as its Distinguished Public Interest Attorney in Residence. In 2009, the law school named him as its Adjunct Professor of the Year. In 2013, he received Touro’s Annual Award “In Recognition of Devoted Service to the Ideals and Purpose of Legal Education,” which in the past, had been reserved only for full-time faculty. During that same year, Touro’s Moot Court Honors Board presented him with the Annual Hon. George C. Pratt Award in Appellate Advocacy, in recognition of his work with the law school’s competitive moot court teams. In 2014, 2015, 2018, 2019 and 2023, Judge Cohen was voted Touro’s Best Adjunct Professor by the law school’s Student Bar Association.

In 2022, the New York State Court of Claims honored Judge Cohen with its Judicial Achievement Award. He has also been a member of the New York State Court System’s Judicial Advisory Committee on Evidence since 2016 and served as a member of the State CLE Board from 2018-2021.

Judge Cohen was the Deputy Director and Chief Counsel of the New York State Office of Homeland Security from 2001 to 2006. During that time, he also served as Acting Director for the Office and Assistant Director for its Legal Division and held a Top-Secret security clearance.

Judge Cohen was an Assistant District Attorney in the Suffolk County, New York District Attorney’s Office from 1976 through 2001 and served as Chief Assistant District Attorney for thirteen years under two elected District Attorneys. He also was Chief of the Office’s Appeals Bureau and Deputy Chief of the Special Investigations Unit. As a prosecutor, Judge Cohen argued more than 200 cases in the Appellate Division, Second Department, more than 20 cases in the New York Court of Appeals and 10 cases in the United States Court of Appeals for the Second Circuit.

Judge Cohen has spoken extensively to judicial, governmental, bar, professional, and academic organizations across the country and has lectured for or been a member of the faculty of the New York State Judicial Institute, various Judicial Associations, the National College of District Attorneys, the New York Prosecutors Training Institute, and the Federal Law Enforcement Training Center. He is a past-President and served on the Board of Directors of the Association of Government Attorneys in Capital Litigation and served as a Legislative Secretary and Treasurer for the New York State District Attorneys’ Association. He was honored by the Suffolk County Court Officers’ Association as its 2020 Judge of the Year and in 2018, the Suffolk Criminal Bar Association named Judge Cohen as “Judge of the Year” as well.

Judge Cohen is a graduate of Columbia College, Columbia University, and the Hofstra University School of Law, where he was a member and editor of the Law Review. Upon graduation from law school, he was an appellate law clerk in Boston, Massachusetts.

Judge Cohen has received the New York State District Attorneys Association’s highest honor, the Frank S. Hogan Award, and is the only non-elected or non-acting recipient ever given this award. In 2025 Judge Cohen received the Builder's Award from Touro Law.