This article examines the phenomenon whereby ‘professionalism’ is used as a concept in higher education (HE), specifically regarding HE’s relationships with professions in science, technology, engineering and mathematics (STEM). We examine the implications for human development arising from the influence of professionalism in HE, presenting the qualitative interpretations of second-career academics, a term we use to describe university teaching staff recruited for their prior industrial experience in STEM professions. Using a phenomenographic approach, we examine the conception of second-career academics and how professionalism influences educational policy and practice in HE. We present four successively inclusive conceptions of experiences, with professionalism expressed as making normative judgements of students’ interactions and behaviours, negotiating those interactions and behaviours with students, critiquing the professional applicability of curricula and activities, and changing those curricula and activities to suit the needs of STEM professions. These conceptions expose challenges related to policy and practice and the roles undertaken by second-career academics, including their enculturation of students into the normative expectations of STEM professions, their influence on the apparent correspondence between HE and work in STEM, and their marketing of STEM professions inside HE.