This study aims to identify the key elements that should be included in a methodological model to evaluate the sustainability of smart cities and examines the case of Medellín, Colombia, from 2020 to 2021. For this purpose, it adopted a qualitative descriptive methodology divided into three stages: (1) reviewing existing methodologies for smart city evaluation; (2) designing, validating, and administering information collection instruments; and (3) systematizing and analyzing in-depth interviews. The results indicate that the said model should focus on six key variables: government, mobility, sustainability, people, economy, and quality of life. Smart cities should generate synergies, ensuring the interoperability of their services so that their inhabitants have a better quality of life. The added value of the model proposed here is that it incorporates social and political dynamics, which is noteworthy because most tools in this field do not prioritize them and focus on technical, environmental, transportation, planning, and technological factors.