This study employs the Delphi–interpretive structural modelling (ISM) approach to uncover and model factors influencing team performance in external audit. In Delphi interviews, 73 factors were identified, and a subsequent survey revealed 13 crucial factors. Among these, supervisor competence, team members' knowledge, and managers/supervisors' supportive attitudes were emphasized as top priorities among the essential 13 factors. These factors serve as guiding principles for interactions, shaping behaviour and attitudes. Notably, this study goes beyond previous research, which typically focussed on a limited number of factors, by identifying 73 factors influencing audit team performance and then determining and modelling the most critical factors based on expert insights. It also sheds light on the underappreciated role of supervisors, often overshadowed by audit managers or partners. Moreover, the study links these factors with transformational, servant, and ethical leadership theories, fostering a more balanced approach to future research in the auditing profession.