Do transformational leaders enhance their followers' daily work engagement?

This diary study investigated whether and how supervisors' leadership style influences followers' daily work engagement. On the basis of leadership theories and the job demands-resources model, we predicted that a transformational leadership style enhances employees' work engagement through the mediation of self-efficacy and optimism, on a day-to-day basis. Forty-two employees first filled in a general questionnaire, and then a diary survey over five consecutive workdays. The results of multilevel analyses offered partial support for our hypotheses. Daily transformational leadership related positively to employees' daily engagement, and day-levels of optimism fully mediated this relationship. However, daily self-efficacy did not act as a mediator. These findings expand theory and previous research by illuminating the role of transformational leaders in fostering employee work engagement. © 2010 Elsevier Inc.