Background: The central point of this study is team initiative, and we analyzed how the theoretical model of antecedents and consequents of personal initiative contribute to explaining the relationship between team initiative and its antecedents and consequents. Authentic leadership is proposed as the antecedent, and the consequent leads to two types of outcomes, one of which is related to employee well-being, and the other is related to performance. However, little is known about what occurs in this relationship once the focus shifts to the team level. From a team perspective, with the label team initiative, we propose a collective construct defined similarly to personal initiative. This study shows the relationship between team initiative and its two consequences, team work engagement and performance, which are measured in terms of team productivity by the leader. Methods: Our model was tested in a field study with 344 employees of 79 work teams belonging to 55 organizations. Results: The analysis of the results using SEM and a regression analysis supported our main hypotheses. Conclusions: The finding that initiative is related to performance establishes the importance of initiative at the team level. It also emphasizes its impact on employee well-being through team work engagement and suggests the importance of authentic leadership.