AbstractThe initiative of project managers gives organizations competitive advantages. This study investigated the role of personal resources (i.e., psychological capital) in driving such behavior. We considered the intervening mechanism of the influence of psychological capital on initiative behavior by treating work engagement as a mediator, and treating job resources (i.e., decision authority) as a reinforcing variable in this relationship. Hypotheses are proposed integrating the literature of psychological capital and the job demands–resources theory. Using a 1-month time-lag questionnaire design, data were collected from 150 project managers responsible for construction projects. It was found that psychological capital has a positive influence on project initiative behavior, and work engagement mediates this influence. Decision authority reinforces the direct influence of psychological capital on work engagement and its indirect influence on project initiative behavior. This research contributes to that on antecedents and formation mechanisms of project initiative behavior and brings new insight to the job demands–resources theory by confirming the reinforcing interaction between psychological capital and decision authority.