This paper presents a Glaserian grounded theory study of adult students’ holistic professional growth in a two-year tailored, work-related, teacher qualification program in physical education. The data consisted of reflective learning diaries, interviews and the written texts of 20 adult students. The data analysis followed the stages of Glaserian grounded theory analysis with substantive and theoretical coding processes carried out using the constant comparative method. The article presents the emotional core and its properties (criticality, ethicality and empowerment) of physical education teacher students’ professional growth. In addition, the article introduces a substantive theory of a process of adult students’ multifaceted professional growth during a work-related physical education teacher-qualification program and discusses the pedagogical implications in relation to developing teacher education in general and the education of physical education teachers in particular.