Baker earned his bachelors, masters and Ph.D.s all from Harvard University. He began teaching at Harvard in 1928 and joined Harvard Business School faculty in 1936. He left Harvard and joined the Civil Aeronautics Board in 1942. In 1945 he became the director of the Office of Transport and Communications Policy for the United States Department of State. From 1946-1956 he served as the United States member of the United Nations Transport and Communications Commission. In 1946 Baker also returned to Harvard Business School as the James J. Hill Professor of Transportation.