Background: Physical education teacher behaviour has been a subject of study in physical education including physical education teacher education for 30 years. However, the research on teacher behaviour has tended to focus on direct teaching behaviour (DTB) to demonstrate the benefits of effective teaching, centred on a technical understanding of the process of teacher behaviour. A holistic approach for teaching behaviour is needed in order to give students educational experiences. Aims: Drawing on the studies of implicit ways of teaching, the aim of this paper is to provide a new approach of researching teacher behaviour in order to understand the social and moral assumptions and to promote students' motivation to engage in physical activities that are embedded in the act of teaching in physical education through the identification of indirect teaching behaviour (ITB). Method: An ethnographically informed case study based on participant observation (eight months) was employed. The researcher observed students in two 8th-grade (13 years old) co-ed physical education classes in South Korea. Participant observation was supported by participant observer field notes, audio/video recordings of classes, questionnaires, and interviews. Findings: Through inductive analysis of the data, the multiple ITBs were identified including tone of voice and intonation, humour, facial expressions and gestures, dress code and setting an example, touch, encouragement, and care. ITB had a powerful influence on students' social and moral development in terms of reflecting on themselves by the teacher's positive modelling, cooperating with other friends and learning the intrinsic value of physical activities and sports. ITB was also found to impact the student's perceptions of physical education and their physical education teachers, which seems to encourage them to learn more about the lesson. Conclusions: An understanding of ITB will help broaden the perspectives on teaching methods used and studies conducted in physical education beyond the dominant approach of DTBs. Teachers need to reflect upon their behaviour in the physical education class, even if their teaching behaviours are regarded as trivial. Furthermore, the understanding of ITB can also play a pivotal role in encouraging pupils to enjoy the intrinsic value of physical education centred on moral values, and fostering a passion for physical activity that extends into participation for life. In this sense, this insight suggests that researchers re-examine the power of ITB in relation to teachers' professional competence. Teacher educators need to intentionally cultivate the character of teacher candidates in their professional preparation phase in addition to ITB-related studies in physical education.