Climate change threatens physical and mental health. Hospitals have a key role in adapting to these impacts. At the same time, hospitals contribute to climate change due to their greenhouse gas emissions. To effectively reduce these emissions, stakeholder involvement is important. This study aimed at identifying possible mitigation measures, barriers, and enablers for their implementation from stakeholders’ perspectives in a German university hospital. We conducted a qualitative study with semi-structured interviews at Heidelberg University Hospital. The participants’ selection was based on purposive maximum variation sampling. The interviews were transcribed verbatim and analyzed using the framework approach, supported by NVivo. Five patients, twelve clinical and twelve administrative employees at different hierarchical levels were interviewed. Stakeholders suggested various possible mitigation measures. Only a few of them were specific to hospitals. Enablers and barriers were attributed to the structural, organizational, mitigation measure, and stakeholder levels. Common barriers on these levels were non-demanding policies, the complexity of organizational structures, the perceived risk of reduced healthcare performance, and lack of awareness and prioritization. Participants formulated enablers, e.g., knowing best-practice examples or hiring a sustainability manager. However, enablers were mostly hypothetical and based on perceived barriers. Profound changes in regulatory frameworks and organizational management would support stakeholders at the investigated hospital in implementing mitigation measures. Furthermore, intensified research about climate-friendly health care and communication of these findings to hospital stakeholders as well as integration of these findings into curricula of the health workforce seems necessary for the climate-friendly transformation of hospitals.