<p>Biosynthetic strategies have emerged as sustainable and eco-friendly alternatives for the fabrication of nanoparticles with multifunctional properties and promising biomedical applications. Among various biological systems, plant-associated microorganisms have attracted increasing interest due to their ability to mediate green synthesis processes. Endophytic microbes, which inhabit internal plant tissues in a symbiotic relationship, constitute a diverse and metabolically rich reservoir of secondary metabolites capable of reducing metal ions into stable nanoparticles. These bioactive metabolites not only facilitate nanoparticle formation but also influence their physicochemical characteristics and biological performance. Although several studies have reported the successful synthesis of silver nanoparticles using endophytic fungi and bacteria, a comprehensive understanding of their biosynthetic mechanisms and application-oriented properties remains fragmented. The present review systematically evaluates published literature to compare the physical, chemical, and biological attributes of silver nanoparticles derived from endophytic microorganisms. In addition, this article elucidates the underlying biosynthetic mechanisms involved in nanoparticle formation and highlights their pharmacognostic potential, including antimicrobial, antioxidant, and anticancer activities. By integrating current knowledge within the framework of plant–endophyte interactions, this review identifies critical research gaps and future directions. Further investigations are warranted to clarify the molecular basis of endophyte-mediated nanoparticle synthesis and to advance their biopharmaceutical applications in sustainable plant-based biotechnology.</p>