After graduating MA with 1st-class honors at the University of Canterbury, Christchurch, Wilson moved to London in 1967 to study for his PhD under the supervision of Professor Hans Eysenck, with whom he subsequently collaborated on a number of research projects and co-authored six books. He also co-authored the Eysenck Personality Profiler, a standard personality test used in clinical research and industry. With John Patterson, he devised the Wilson-Patterson Conservatism Scale, which remains one of the most widely used measures in social attitude research. His 1973 theory that a heritable trait reflecting fear of uncertainty underlies social attitudes in all fields has much empirical support. Together with G.Knyazev and H.Slobodskaya of the Russian Academy of Medical Sciences, Wilson has researched the EEG correlates of personality and produced a theory of the evolution of brain oscillations.

Wilson was a pioneer of evolutionary approaches to understanding human sex differences and mating behavior, attracting some hostility when this was unfashionable in the 1970s. His use of the bust-waist ratio as an objective index of female sexual attractiveness presaged the waist-hip ratio, now widely accepted as an oestrogen (fertility) marker. His studies of sex fantasy yielded the Wilson Sex Fantasy Questionnaire, often used in research and forensic psychology. Noting that men and women had different finger length patterns, Wilson introduced the 2D/4D digit ratio as a marker of exposure to prenatal testosterone, research on which has burgeoned in recent decades. His work, with Jon Cousins, in developing the compatibility quotient (CQ) as a predictor of relationship success has resulted in his characterization as "the father of modern compatibility testing". With Qazi Rahman, Wilson has published research supporting the conclusion that sexual orientation is of constitutional origin.

An interest in music and singing (he is a part-time professional baritone) led to courses on Psychology of Performance, which he has taught both in the US and UK. His book Psychology for Performing Artists, now in its 2nd edition, is a standard text in music and drama schools.

From 1994 until 2008, Wilson was Reader in Personality at the Institute of Psychiatry, King's College, University of London. He has held visiting appointments at several American institutions, including California State University, Los Angeles, Stanford University, San Francisco State University, Sierra Nevada College and the University of Nevada, Reno, where he was Adjunct Professor for many years. He is currently Visiting Professor of Psychology at Gresham College, London.