His law career was quite extensive, and his professional memberships included Fellow of the American Bar Foundation, the American Bar Association, the Essex County and Somerset County Bar Associations, and the American Judicature Society.
American | American Civil War | American Broadcasting Company | American football | African American | American Idol | American Revolutionary War | American Revolution | Society of Jesus | Royal Society | American Association for the Advancement of Science | American Red Cross | National Geographic Society | American Library Association | American Museum of Natural History | American Express | American Academy of Arts and Sciences | American League | American Association | American Heart Association | American comic book | American Institute of Architects | American Airlines | American Hockey League | Spanish-American War | Pan American Games | American Cancer Society | Whitney Museum of American Art | American Ballet Theatre | American Legion |
An avid hunter and fisherman, he was also a member of the American Bar Association, the American Judicature Society, the Freemasons, and the Optimist Club.
Gillespie was a member of the Association of the Bar of the City of New York, Federal and American Bar Associations, the New York County Lawyers Association, the American Judicature Society, the Council on Foreign Relations, and the Skull and Bones society at Yale.