Organization Alpha Delta Phi

United States Marine Corps

American Academy of Arts and Letters

Modern Language Association of America (honorary member)

Authors Guild

Actors Equity Association

Hispanic Society of America (corresponding member)

Akademie der Wissenschaften und der Literatur (West Germany)

Bavarian Academy of Fine Arts (honorary member)

Century Association

Players (honorary member)

Graduate Club

Elizabethan Club

United States Army (WWI ∙ WWII)

Harvard University (Charles Eliot Norton professor)

University of Chicago (professor)

Institut de Cooperation Intellectuélle ( [1937])

United States Department of State

International PEN Club Congress ( [1941])

UNESCO Conference of Arts ( [1952])

Lawrenceville School, Lawrenceville, New Jersey, USA (teacher)

March of Dimes (founder)

American Philosophical Association

Ethical Culture Society

Metaphysical Society of America

Columbia University

New York Civic Club

Opportunity: Journal of Negro Life

Frederick Douglass Junior High School

Woodrow Wilson Administration

League of Nations Commission on Mandates

American Ornithologists' Union

Cornell University Glee Club

Sphinx Head Society

Cornell University