Before joining the New Zealand Business Roundtable, he worked as an assistant secretary at the New Zealand Treasury and as a senior figure in the Ministry of Foreign Affairs including as a diplomat in Brussels.
Before joining the New Zealand Business Roundtable, he joined the New Zealand Treasury at age 32 at became Director of Economics II in 1981 and subsequently became an assistant secretary. Prior to Kerr's time at the Treasury he worked at Ministry of Foreign Affairs including as a diplomat in Brussels.