As we reach the fifth anniversary of the Declaration of the United Nations 2030 Agenda for Sustainable Development, the tourism sector responsible for over 10% of the world’s GDP still does not have an open-source, sustainable management criteria that would enable and empower them to “walk the talk” to contribute to the Sustainable Development Goals (SDGs). The purpose of this paper is to fill the gap in the social sciences and business management literature by providing a theoretical Sustainable Strategic Management Model (SSMM) proposal for the Fourth Sector (4S), Small- and Medium-sized (SMEs) Hotel companies (4S-SM-HCs), which are committed and have the will to contribute firmly to the 2030 Agenda. Based on their corporate purpose and aligned with the SDGs, this article provides a holistic proposal with a multi-stakeholder approach, adding the SDG perspective. Through a qualitative research methodology based on two focus groups in which the main stakeholders and the management team of the 4S-SM-HC under examination took part, a theoretical SSMM is co-defined so that the hotel company can make significant contributions to the five areas of the SDGs. Basing their structure on the internationally recognized Global Sustainable Tourism Council (GSTC) Criteria and co-created through social learning, this SSMM proposes four strategic management axis and develops ten principles of ethical performance (PEP). The main contributions of this article are two: (1) to provide an ecosystemic SSMM proposal to the 4S-SM-HCs to allow them to make significant contributions to the SDGs, and (2) to facilitate a methodological framework with a multi-stakeholder approach and SDG perspective to enable them to contribute to the wellbeing of people, the community and the planet.