He completed his first year of Princeton University in 1940 but was forced to leave when his vision degenerated.

In 1966 he took a two-year sabbatical to work as a special assistant on oceanography and foreign affairs for Senator Claiborne Pell.

He resigned from USIA in 1970 and ran unsuccessfully for the Republican nomination for a Congressional seat from Rhode Island.

Green returned to government service as associate administrator of the Environmental Protection Agency from 1971 to 1977 and 1983–1987.

On retirement from the EPA, Green joined the private enterprise of William D. Ruckelshaus Associates as vice president of international operations.