Objective Collaborative practice is critical to optimising patient outcomes in contemporary healthcare settings. Evidence suggests interprofessional learning is an effective way to develop teamwork capabilities, yet these skills are traditionally developed in professional silos, or not at all. This study evaluated the implementation of a team development program, the Team Management Systems (TMS) program, for allied health staff within a large metropolitan health service. Methods A mixed-methods audit-quality improvement study was conducted, using Kirkpatrick's four-level evaluation model to structure evaluation of the program. Semistructured questionnaire and workforce survey data were retrieved immediately, 6 months and 1-2 years after training and applied to each level of the model (Reaction, Learning, Behaviour, Results). Results In all, 886 staff participated in the TMS program from 2014 to 2018. High satisfaction with the program was observed. Knowledge of what constitutes effective teamwork improved significantly (P=0.008) in TMS participants compared with a matched untrained cohort. Participants reported positive behaviour change and continued engagement with TMS principles 6 months after training. Perceived impact of the program on patient and/or organisational outcomes was evident, although less compelling than the changes to knowledge and behaviour. Conclusions The TMS program yielded positive effects on staff satisfaction, knowledge, team dynamics and team behaviours. These findings demonstrate the significant value of such initiatives to enhance the capability and effectiveness of interdisciplinary healthcare teams. What is known about the topic? Complex conditions, increasing comorbidities, specialisation and scarcity of resources mean healthcare workers need to work effectively in teams to achieve quality, safe, person centred patient care. There is some evidence of the effect of teamwork initiatives on knowledge or behaviour in specific clinical specialities, single services or single professions, but limited research is available regarding the effects of teamwork programs across multiple professions, including allied health professions, and on patient and organisational outcomes. What does this paper add? This paper describes the effect of a large-scale teamwork program implemented across multiple professions, including enablers and barriers. It presents outcomes at all four levels of Kirkpatrick's evaluation model, including the less studied behaviour and results levels. What are the implications for practitioners? This paper supports health service leaders to consider developing and implementing interprofessional teamwork programs to foster essential teamwork capabilities. Learning together about teamwork, across professional silos, will lead to collaborative, patient-centred care, which leads to safe, quality patient outcomes.