[1] Before joining Treasury, Whitehead worked in the Statistics Department and was Deputy Director of the Labour Party Research Unit (1977–82).

[citation needed] Between 1985 and 1992, he worked as an Economic Adviser in the Prime Minister's Office and David Lange's government (1985–88), and as a Minister (Economic) at the New Zealand High Commission in London.

[2] In the 2011 Queen's Birthday Honours, Whitehead was appointed a Companion of the New Zealand Order of Merit, for services as Secretary to the Treasury.

[3] Whitehead was a World Bank Executive Director from August 2011 to July 2013 for Australia, Cambodia, Kiribati, Republic of Korea, Marshall Islands, Federated States of Micronesia, Mongolia, New Zealand, Palau, Papua New Guinea, Samoa, Solomon Islands, Tuvalu and Vanuatu.

[7] He was appointed chancellor and chair of the national priory board of St John New Zealand for a three-year term from 24 June 2020.