In the United States, cross-sector partnerships, a form of collaboration, are becoming increasingly common in practice (Gray & Purdy, 2018). However, questions remain regarding the effectiveness of these partnerships and if the many challenges of using them can be overcome. In particular, the intersection of cross-sector partnerships and power, which can deeply impact these partnerships, needs more attention. This study used interpretive phenomenology to understand, from the participant perspective, (a) the experience and construction of power, (b) the impact of power on participants, and (c) how power dynamics in these initiatives compare to dynamics in organizations. Seventeen participants from four homelessness-focused Collective Impact (CI) initiatives, a popular cross-sector partnership model, were interviewed about their experiences. In addition, I reviewed key documents about each initiative. Data was interpreted using a variety of theoretical lenses, including critical theory, as well as my own work experience in this area, and carefully analyzed through iterative re-engagement, reflexivity, and thematic analysis. The findings revealed that power presented in six different ways: resources, structures and processes, identity, resistance, formal leadership, and framing and communication. When examining the differences between collaborations, differences in these six areas, as well as the identity and ways of operating of the partner who began the partnership, seemed to influence the experience of power. Financial resources were a dominant form of power and provided some partners with disproportionate influence. Dominant partners were also able to stack power across these six areas. The impacts of power dynamics were largely negative. Other significant findings included that some partners did not experience power at all. Critical theory and positive framing may explain this outcome. I call for an expanded CI model with a sixth condition related to power. As part of this sixth condition, I suggest communities make structural changes, such as, to honor discursive power more effectively, putting consumers in positions of power and rotating facilitation responsibilities. This dissertation is available in open access at AURA: Antioch University Repository and Archive, http://aura.antioch.edu/ and Ohiolink ETD Center, https://etd.ohiolink.edu/ Advisors/Committee Members: Booysen, Lize (A.E.) (Committee Chair).