He graduated from Yale University in 1963 with a BA in history, following which he spent two years teaching in Dallas, Texas.

He was the first career diplomat in modern history to be made Ambassador to the UK – the post is usually given to a political appointee.

Since retiring from the foreign service, Seitz has held numerous directorships, governorships, and trusteeships.

He has held non-executive directorships on the boards of British Airways, Hong Kong Telecom, Marconi, General Electric Co, Rio Tinto Group and Cable & Wireless.

He was a trustee of the National Gallery between 1996 and 2001 and was a member of the Founding Council of the Rothermere American Institute, University of Oxford.