This article is based on research about upper secondary students' experiences in vocational becoming as they develop conceptualized knowing through interactions with others. Interactions for meaning-making by vocationalising concepts also involve feedback relating to occupation-specific tasks. The aim was to understand this constructivist process of occupational identity formation - a goal of vocational education. The research reported here draws on data from participant observations and focus group interviews with 34 students in 2nd and 3rd grades in two schools, who were training to become security officers. Students vocationalise five features of security practices: (i) transforming anomaly into specialized concept; (ii) the uniform as a marker; (iii) accountability to the security industry through zero limit; (iv) modernizing the security occupation; and (v) social, study and professional conduct. The findings indicate that processual feedback supports the development of vocational conceptual knowing inferentially in the space of reasons. Teacher-led processual feedback provides more opportunities for vocationalising concepts, whereas student-led feedback during group work offers fewer such opportunities, although it does strengthen student identity. Overall, the findings show that collective meaning-making, supported by processual feedback, contributes to the construction of specialized knowledge for vocational becoming, thus leading to emergent vocational identity. However, making firm decisions about a chosen vocation takes time, and this appears challenging especially for youth with their limited life experiences (Tanggaard in Journal of Education and Work, 20(5), 453–466, 2007). For many prospective security officers, their vantage point remains uncertain, as they imagine, deliberate and put expectations to a reality check during the course of their study.