After his graduation he started his academic career as researcher at the Psychological Laboratory of the Radboud University Nijmegen in the 1960s.
[4] Kempen's early research had focussed on "The strategy of peace in sociological perspective",[5] and he published another article about "Psychology and the problems of war prevention and peacebuilding".
[6] In 1972, he edited his first publication with Vimala Thakar[7] In the 1972 unpublished article, entitled "From the cabinet of exotic comportment to a general theory of behavior", he gave a sketch of his "cultural psychology, that was critical of psychology itself, but at the same time stimulating all of us to look beyond culture.
Among his students were Jürgen Straub, German Professor of intercultural communication,;[8] Hub Zwart, Professor of Philosophy at the Radboud University Nijmegen;[9] Paul Voestermans (who in 1970 was the only student placed under Kempen's supervision; on Kempen's initiative he joint the University of Colorado in June, 1971 till November,1972 to study with Richard Jessor at the Institute of Behavioral Science, CU, Boulder, Colorado.
"[14] In the 1990s, Kempen and Hubert Hermans developed a new approach in cultural psychology around the concept of the dialogical self.