Universities are under mounting pressure to partner with societal stakeholders and organizations to collaboratively create and implement sustainability-advancing knowledge, tools, and societal transformations. Simultaneously, an increasing number of societal organizations are reaching out to partner with universities to achieve organizational objectives and increase the effectiveness of strategies to further societal sustainability. Using a conceptual framework of "sustainability co-creation", this study empirically examines the historical and ongoing experiences of five organizations in Japan that actively partner with universities to enhance sustainability activities and strategies to transform society. We examine motivations for partnering with universities, innovative models of practice, factors hampering the co-creative potential of the university, and desired changes to overcome these. Our empirical study leads to the proposal of a typology that might assist in categorizing and understanding key attributes of differing types of sustainability co-creation. We build our typology from two perspectives: First, in terms of the primary objective of the co-creation (ranging from knowledge production to the transformation of society), and second, in terms of the approach taken (ranging from either socially or technologically-centered). We then reflect on the organizations' experiences to offer several strategies that could increase the effectiveness of the university when partnering with stakeholders in sustainability co-creation. We also highlight several factors effecting the university's capacity to move beyond knowledge production towards implementation measures to transform society with external stakeholders.