The increasing global demand for sustainable production practices has propelled green manufacturing to the forefront of industrial innovation. Central to this movement is the integration of smart sensors for real-time data collection, an approach that promises significant advancements in waste reduction and energy efficiency. This chapter explores how smart sensor technology can transform traditional manufacturing processes by enabling continuous monitoring, data-driven decision-making, and predictive maintenance. Through a comprehensive review of real-time monitoring applications, the chapter discusses various sensor types, their roles in capturing critical data on emissions, resource consumption, and waste outputs, and their integration into green manufacturing systems. Case studies from diverse industries illustrate the substantial impact of smart sensors in optimising energy use, reducing material waste, and supporting circular economy models. Further, the chapter examines the technical challenges and data privacy considerations associated with real-time monitoring and proposes solutions to enhance adoption. By leveraging intelligent data analytics and Internet of Things (IoT) connectivity, manufacturers can achieve a more responsive, eco-friendly production environment. This chapter concludes with a discussion on the future implications of smart sensor technology in green manufacturing, highlighting the role of regulatory standards and industry partnerships in driving innovation for a sustainable future.