This study summarizes the transformative influence of digitalization on maintenance, a key component of asset management, with particular emphasis on the transition from traditional maintenance practices to Smart Maintenance paradigms. For that, peer-reviewed and industrial research are analysed using a narrative review methodology, to identify how emerging digital technologies are reshaping maintenance processes, decision-making mechanisms, along with human and organizational dynamics. Methodologically, the review adopts a structured approach to map the historic evolution of digital maintenance, to classify the main technological and managerial enablers driving this transformation. It continues by exploring the challenges that hinder its large-scale implementation, such as data interoperability, cybersecurity, and workforce reskilling. Additionally, the research also presents some of the most relevant Smart Maintenance frameworks found in the literature, along with some implementation cases of different sectors. Thus, this research provides a comprehensive synthesis of current developments, highlights critical gaps in the literature, and outlines future research directions aimed at advancing the digital transformation of asset management and, within it, Smart Maintenance systems.