This article answers the call for more research on Millennials' experience of the graduate transition to work (GTW). Using an identity perspective, it investigates how Millennials explored and developed their career identities after the GTW, with a particular focus on traits often associated with younger generations such as boundaryless, protean and intrinsic motivations. Interviews were conducted with 36 Millennial graduates from U.k. and Irish universities. Findings confirmed that graduates largely avoided identity exploration until the GTW, with the latter perceived as a boundary experience and self-learning event. Four main themes of identity work developed from the data analysis: restraining the ideal self; reasserting the ideal self; revising the ideal self; and re-exploring possible selves. Participants appeared to increase their adaptability, self-drive and intrinsic motivation after the GTW in a way different from previous generations. Moreover, they continued to develop and change their career-identities long after the first few transitional years. Implications for Higher Education and organisational practice are accordingly discussed.