Pre-service teacher mental health during professional experience is receiving growing academic attention, particularly given the increasing numbers of pre-service teachers across Australia who are currently being conditionally approved and employed to teach while completing study to address teacher shortages. As such, it is becoming apparent that it is important to study the potential impact of competing academic and professional demands on pre-service teacher wellbeing and mental health. This study used a cross-sectional approach to collect quantitative and qualitative data from 166 regional university pre-service teachers completing their initial teacher education degrees in NSW, Australia. Quantitative results showed that higher psychological distress exhibited in pre-service teachers was associated with poorer pre-service teacher wellbeing, sense of connectedness, and self-efficacy. Qualitative results suggested that the influence of teaching mentors and tertiary supervisors mediated these outcomes. Implications are discussed including providing supervisors mental health training to appropriately support pre-service teachers.