When Harris joined Stanford's Department of Economics in 1972, he became the first Black scholar to be granted tenure there — a landmark moment in the history of one of the world's most prestigious economics departments. He went on to teach there for nearly three decades, mentoring doctoral students and developing graduate coursework in alternative approaches to economic analysis.

Harris served as an economic policy consultant and adviser to successive Jamaican prime ministers over several decades. His most notable contributions include helping shape Jamaica's National Industrial Policy in 1996 and co-authoring the Growth Inducement Strategy of 2011 — a framework that some economists credit with enabling Jamaica's later success in achieving sustained growth and significant reductions in public debt.

Harris works within the tradition of Post-Keynesian economics, a school of thought that builds on the ideas of John Maynard Keynes while also drawing heavily on Karl Marx, Piero Sraffa, Michal Kalecki, and Joan Robinson. His approach emphasizes the role of power, class structures, and historical context in shaping economic outcomes — factors he argued that mainstream economic models largely ignore.

Yes — he is her father. Donald Harris met Shyamala Gopalan, a graduate student from India, at UC Berkeley in 1962, and the two married in 1963. Their daughter Kamala Harris was born in 1964 and went on to become the 49th Vice President of the United States. Despite his daughter's prominence, Harris has remained intensely private throughout his life, rarely giving interviews or making public appearances.