Microbial fuel cell (MFC) is a cutting-edge multifunctional technology residing at the interface of power generation and wastewater treatment. By leveraging the bio-electrochemical capabilities of electroactive microorganisms, MFCs offer a dual advantage: addressing environmental concerns with regard to wastewater and participating in generation of renewable energy. This chapter discusses the general and subsystems of MFCs, as well as how the bidirectional syntropy process enables the MFC’s ability to biodegrade organic matter and generate bioelectricity. The talk continues with the general overview of the MFCs usage depending on the wastewater type and their comparability with traditional treatment technologies. MFCs are clearly related to the Sustainable Development Goal 6 (SDG 6) and SDG 7 focusing on clean water and sustainable energy, but the common barriers that technology-based business models experience are specific and general constraints to scale. Recent developments in microbial engineering, material selection and design, and system design, however, suggest viable avenues through which they can be incorporated into efficient smart wastewater management systems and smart circular economy systems. The real-life application of energy recovery pathways and future prospects discussed in this chapter demonstrate that MFCs have the ability to revolutionize conventional thinking and practice in bioenergy generation and wastewater treatment. Finally, it postulates that only with the policy support, innovation, and industrial adoption the potential of MFC technology can be harnessed to its real goal of providing solutions for sustainable development.