His parents, of English and Dutch descent, were Susan Tompkins and John Haven Emerson, a medical doctor.

[2][1] At the end of World War I, Emerson returned to Paris for two years as director of the Bureau of Construction of the American Red Cross.

In his first year, he oversaw the creation of a Department of City Planning, commissioning planner Thomas Adams to create its curriculum.

[3] In conjunction with the planning program, Emerson's seven-year deanship shifted the school from pure design practice to a broader focus on public policy and social issues.

[2][4] Emerson served as the chair of the Unitarian Service Committee in the 1940s and as Vice President of the Byzantine Institute of America.