A more focused and inclusive approach to the conservation of architectural heritage can make a positive cultural, economic and social contribution to the well-being of our society. Architectural heritage has been recognized as a crucial component of sustainable built environment and approaches to conservation of architectural heritage are evolving. The case study of Negova Castle examines the effects of a traditional, object-based approach to conservation of the architectural heritage compared to a reconfigured sustainable approach which supports the importance of sustainable development. Since 2006, the Negova Castle Complex has gone through a thorough restoration process and in 2012 restored buildings were open to the public; the restoration followed traditional object-based conservation practices. The buildings were restored as monuments of the past with little consideration of current social and economic norms. The main building, a 15th century castle, was left untouched due to the lack of financing. The aim of this paper is to provide a brief analysis of the current situation of Negova Castle, to challenge the traditional object-based approach and its criteria for the evaluation of heritage authenticity which was applied to the restored buildings and, subsequently, to identify holistic, sustainable approaches with adaptive reuse strategies suitable for the 15th century castle. By analyzing the Negova Castle project, it becomes evident that it is very hard to protect, preserve and manage the site's architectural heritage for the future without understanding and properly balancing its contemporary and sustained values and without meeting the current social needs. The goal of this study is to propose an approach that addresses the architectural integrity of the Old Castle and to reduce interventions in its fabric while contributing to the greater integration of architectural heritage owners and other stakeholders into the sustainable conservation process and management of the Negova Castle Complex.