He practices in the areas of immigration, consumer and administrative law. To Sheehan, the common strand in such cases is the misuse or abuse of authority/negotiating power by a larger entity (be it a corporation or governmental body) with respect to its more diminutive and generally weaker adversary. Among other activity, Sheehan was co-lead counsel in the first case which challenged food manufacturer's labeling of their products as "raw." Sheehan also represents former subway vigilante Bernard Goetz against his landlord's claims that Goetz possesses "wild squirrels" in his Manhattan apartment. Before becoming an attorney, Sheehan served in the United States Marine Corps. He is a graduate of a Georgetown University (2002) and Fordham University School of Law (2010).