The growing number of today’s leaders represent millennial leaders who have their specific approach to leadership work. This was a phenomenographical study in which 28 Finnish leaders from Great Places to Work companies were interviewed. The purpose was to define the core of millennial leadership. The leadership dimensions of social, psychological, and cognitive-operational leadership were distinguished from the millennial leaders’ perceptions. Social leadership comprised elements that highlighted interpersonal relations in leaders’ work. Psychological leadership evidenced leaders’ positive thinking about human growth and well-being. Successful leadership was seen through “human eyeglasses”. The leader’s strong service mentality as well as practice time and work management represented cognitive-operational leadership. The output of this study is a new perspective of millennial leadership. The developed definition of a successful millennial leadership will help to understand young leaders’ ideas about leadership and organizations to support their development in their work.