The nanotechnology industry fabricates a wide variety of products used in many areas, such as pharmaceutical, medical, civil and space engineering, and day-to-day life. The application of NMs, however, has encountered significant drawbacks such as the high energy costs involved in NM production processes, or the use of hazardous chemicals. Using biogenic protocols to produce NMs includes several advantages for example the use of more eco-friendly chemicals, mild pressure and temperature requirements, reasonable energy demands, and their potential for producing NMs with the desired size range and tailored activities. Many interesting biogenic NMs with antimicrobial activity have been reported attracting a great deal of attention in the treatment of bacterial, fungal, and viral infections. The photocatalytic activity of biogenic NMs and their use in the removal of organic contaminants and inactivation of pathogens in water are topics receiving far less attention. This review paper provides an in-depth review of the state-of-the-art processes currently available to generate biogenic NMs and the technology reported for their characterization, an analysis of their use in the photocatalytic degradation of organic contaminants and inactivation of bacteria in water, and their potential use as antivirals. This study also reviews the major differences between conventional and biogenic NMs, analyzing and undertaking a critical analysis on the feasibility challenges faced by the nanotechnology industry for the engineered use of biogenic NMs, their main advantages and drawbacks, and identifies current knowledge gaps and recommends future research directions. The outcomes of this study provide an in-depth analysis of the potential and feasibility of biogenic nanomaterials for environmental applications.