While the role of the organizational context in enabling leadership behaviours has attracted increasing research attention, the role of leaders’ age in this dynamic has been overlooked. Using transformational leadership theory (Bass, 1985) and Oc’s framework of context (2018), we examine how aspects of the task, social, physical, and temporal context shape leadership behaviour from a lifespan perspective. A random sample of young leaders and their older colleagues was surveyed (n = 847). Multiple group structural equation modelling was used to test the study hypotheses. Results indicated that the task context, in terms of role clarity, was a stronger predictor of transformational leadership among young leaders than it was among their older colleagues. Social, physical, and temporal contexts did not differ in their effect on the leaders’ ability to exhibit transformational leadership. Our findings suggest that organizations can facilitate young leaders’ role clarity to support their development of constructive (i.e. transformational) leadership behaviours. In addition, our study demonstrates that leadership research benefits from a lifespan perspective to facilitate a better understanding of how leaders’ age influences the emergence of leadership behaviour.