Nicholas J. Healy has practiced admiralty since 1936. He received his AB from Holy Cross and JD from Harvard. During World War II, he received a naval commission, but was assigned to duty with the U.S. Attorney's Office in New York. There he handled admiralty cases, mainly involving collisions, for the Navy, Coast Guard, War Shipping Administration, and other government agencies.

He served as special assistant to the Attorney General for several years before forming the predecessor of his law firm, Healy & Baillie.

Healy gave the admiralty course at New York University from 1947 until 1986 and holds the title of adjunct professor of law. He has been a visiting professor of maritime law at Tulane University, Shanghai University, and Temple University. He is a past president of the Maritime Law Association of the United States and a past vice president of the Comité Maritime International. Healy is the coauthor of The Law of Marine Collision.