Rehabilitating heritage buildings is a common practice in developed countries. In contrast, developing countries experiencing conflict lack the financial support and qualified experts to restore heritage buildings. This article focuses on the restoration of the al-Khader building in the Gaza Strip, part of a UNESCO project aimed at preserving historical buildings. This study aims to explore the challenges and impacts of the adaptive reuse of the al-Khader building as a children’s library for the local community and to explore the impact of this project on sustainable development and its importance locally, as well as the role of this building restoration and rehabilitation through Quintuple Helix dimensions. Qualitative methodology was used, including field observation and interviews, to present the project stages during restoration in 2016. The interviews were conducted with library users, employees, and visitors to evaluate their experience in 2019. The research revealed that the restoration process faced several challenges, including a lack of experience and professional workers in conservation work. Despite challenges, the building’s transformation positively affected heritage preservation and the local community, aligning with 11 Sustainable Development Goals—directly with 7 goals (SDGs 4, 7, 8, 11, 12, 16, and 17) and indirectly with 4 goals (SDGs 1, 5, 9, and 13). The findings emphasise the role of the library’s rehabilitation in contributing to the success of the Quintuple Helix in economic and civil society systems and the need to enhance the consideration of government, education, and environmental systems. Finally, this project, which external donors funded, increased awareness among local people of the importance of heritage buildings. Unfortunately, due to the ongoing conflict in Gaza, the current status of the building is unknown. This study, therefore, serves as necessary documentation of the building as it was in 2023 and prior.