[3][4] Green graduated from Kenyon College with highest honors in history in 1983 and received his MA in 1987 and PhD in 1994 from Johns Hopkins SAIS.

He also did graduate work at Tokyo University as a Fulbright fellow and at the Massachusetts Institute of Technology as a research associate of the MIT-Japan Program.

He joined the NSC in April 2001 as director of Asian affairs responsible for Japan, Korea, and Australia/New Zealand.

[11] In August 2016, Green was one of fifty senior GOP national security officials who signed a letter saying they will not vote for Donald Trump, then Republican nominee for president.

Green speaks fluent Japanese and spent over five years in Japan working as an Assistant Language Teacher on a precursor to the JET Programme,[13] as a staff member of the Diet of Japan, as a journalist for Japanese and American newspapers, and as a consultant for U.S. business.