Career development (CD) is a multilevel topic involving both the individual and the organization and influencing outcomes at the individual, group and organization level. The established limitations in current CD theory and human resource development (HRD) theory building can be addressed by examining the topic of CD through a multilevel lens. Using multilevel theory building (MLTB) to bridge the theoretical gap between individuals and organizations, this approach to theory building provides an opportunity for HRD professionals to address goals important to both individuals and organizations. Based on the CD and HRD interests described above, the threefold purpose of this study is to develop a multilevel theory of CD as a means of strengthening the theoretical connection between CD and HRD, advancing theory building in HRD, and contributing to meaningful convergence amongst existing CD theory. A new MLTB framework is developed and subsequently used to develop a multilevel theory of CD. Finally, future research options are suggested in order to make the appropriate theory refinements, continue the dialogue about MLTB and multilevel considerations in HRD, and add to the convergence of CD theory by providing a multilevel perspective of CD.