He was an appointed by President John F. Kennedy to be the first Assistant Secretary of State for Education and Culture in February, 1961. He was an advocate for overhauling the educational system, saying that every school district should put 2% of its money into educational research and hire a "Vice President in charge of heresy. During his stint in this post, he went to live in Paris, organizing the UNESCO International Institute for Educational Planning. This UNESCO-created group advised countries on improvements to their systems of education. Being dissatisfied with the pace of change, he resigned from the State Department in 1962 and from 1963 to 1968 held the post of Director of the IIEP. He served as vice-chair and chair of the International Council of Economic Development until 1992, when he retired.
During his career he wrote several books on foreign policy and education. He was married to Helena Brooks for 65 years and had two children, Peter B. Coombs and Helena H. Weeks.
Problems of economic mobilization (Industrial College of the Armed Forces, Washington, D.C. Economic mobilization course), by Philip H Coombs, 1947