Nicholas P. Iannuzzi was admitted to the Bar of the State of New York on November 10, 1930. Shortly thereafter, he began to work in the private practice of the law in association with Caesar F. Barra, an eminent criminal trial attorney of that day. During this period, Mr. Iannuzzi represented individuals accused of violations of the penal law, including Johnny Torrio and Charles Luciano. Mr. Iannuzzi maintained his own private law practice until 1944 when he was appointed an Assistant United States Attorney in the Southern District of New York.

Following his term in that office, Mr. Iannuzzi became Court Room Attorney/Confidential Assistant to the Honorable James B.M. McNally, Justice of the Supreme Court, State of New York. During this period of time Mr. Iannuzzi was also Attorney for the New York County Democratic Organization (Tammany Hall).

After Completing his public Service, Mr. Iannuzzi re-entered private practice of the law in the City of New York.