This study aimed to empirically measure the effects of immediate leadership on the degree of commitment of Brazilian Generation Y professionals in their work environment. Specifically, it was aimed to understand the Leader's action through the Full Range Leadership approach, which involves the Transformational, Transactional, and Laissez-faire components, and their correlations with Organizational Commitment, as well as the relationships between Commitment, Performance, extra effort, satisfaction, effectiveness and willingness to stay in the organization. In order to pursue this research, an instrument was used to measure the perception of the leader's action and the degree of organizational commitment, using the survey method. A sample of 732 valid responses was obtained. After characterization of the sample, multivariate statistical data analysis techniques were applied by means of the structural equation model (SEM). It was found that the Leader demonstrates Intellectual Stimulation generates Commitment, however, contrary to what was expected in the literature, it was observed that the Leader who demonstrate Idealized Influence, also generates a higher degree of Commitment. Individualized Consideration and Inspiring Motivation, components of the Transformational model and expected predictors of Commitment have not been proven. This research also suggested that Gen Y high performers are those who report that they have a strong connection of sympathy and affection for the organization, are interested in the company's destinies, take the organization's goals as their own, and address the organization's problems as their own. On the other hand, the excellent performance of these professionals is not necessarily related to the pride of saying they are part of the organization, finding personal meaning in working in the company, good word of mouth about the organization to friends, inspiring the best of oneself or identifying with the values of the organization, despite the fact that those factors are also part of the measurement instrument for the degree of Commitment.