He served as a housing, infrastructure, and real estate consultant to global corporations and government agencies, and a non-resident Senior Advisor at the Center for Strategic and International Studies (CSIS).

In 1968, he joined McKinsey, transferring to London in 1970, where he consulted on British and European housing, real estate, urban development, and local government issues.

He wrote policy guidelines called The Sunderland Study: Tackling Urban Problems for the UK government, and advised private firms on real estate strategy.

He has advised over 200 companies, institutions and governments in 13 countries on some 600 projects, including Irvine and Playa Vista, California; Brandermill, Virginia; Disney World; Hull, London, and Sunderland in the United Kingdom; the Villes Nouvelles in France; and business new communities in Japan.

Apgar received the Army's Decoration for Distinguished Civilian Service, the first Chairman's Award of the President's Advisory Council on Historic Preservation and the Arthur A.