Derek began his tertiary career as a Biochemistry teacher at Otago University and then Otago Polytechnic. He then took on the role as national leader of Association of Staff in Tertiary Education, one of the two education unions that later combined to create the current Tertiary Education Union. Moving then into education management, Derek became one of the architects of the transformation of Auckland Institute of Technology to Auckland University of Technology, becoming its Vice Chancellor in 2004. For the next 18 years, he led the advance of the new university into a major contributor of excellence and equity in higher education.

Derek has served on numerous governance and advisory boards, often as Chair, from institutional Academic Boards and Councils to national bodies such as the Authority for Advanced Vocational Awards, New Zealand Qualifications Authority, the Committee on University Academic Programmes, and Universities New Zealand, as well as various community and private education boards. Derek's governance experience also extends to the health, arts, and sport sectors at local and national levels.