Joshua Deahl

Joshua Adam Deahl (born February 13, 1981) is an American attorney who has served as an associate judge on the District of Columbia Court of Appeals since January 2020.

Education and career Deahl earned his Bachelor of Arts from Arizona State University in 2003 and his Juris Doctor from University of Michigan Law School in 2006.

After graduating from law school, Deahl clerked for Court of Appeals for the Fifth Circuit Judge Fortunato Benavides Deahl worked as an attorney for the Public Defender Service for the District of Columbia and in private practice. His nomination expired on January 4, 2019, with the end of the 115th United States Congress.

Trump renominated Deahl on May 2, 2019, to a 15-year term as an associate judge on the District of Columbia Court of Appeals to the seat vacated by Eric T. Washington. On October 22, 2019, the Senate Committee on Homeland Security and Governmental Affairs held a hearing on his nomination. On November 6, 2019, the Committee reported his nomination favorably to the senate floor. On November 21, 2019, the full Senate confirmed his nomination by voice vote.

AI in the Law

Judge Deahl was one of the first judges to openly use AI in a judicial opinion when, in a dissent, he shared some exchanges he had with an LLM when scrutinizing his view that one could say beyond a reasonable doubt that there was a "plain and strong likelihood" that a dog left in a car in 98 degree heat for 1 hour and 20 minutes would be harmed.

In the fall of 2025, Judge Deahl co-taught the first law school course focused on AI use in the judiciary. He is teaching a similar course, AI in Appellate Practice and Judicial Decisionmaking, at UChicago Law in the fall semester of 2026.