<p>The leather industry is a significant contributor to the global economy, yet it generates considerable amounts of solid waste, including raw hides, hair, chrome shaving waste, vegetable-tanned waste, buffing dust, and trimming waste. These leather solid wastes are rich in carbon and nitrogen and hold potential for repurposing in energy-related applications, thus offering an innovative solution to the industry’s waste management issues. This review explores the applications of leather waste in the development of thermal and electrical energy storage devices, such as supercapacitors and batteries, due to its high surface area, mechanical strength, thermal stability, and electrical conductivity. Additionally, leather waste shows promise in bioelectricity generation through microbial fuel cells and as electrocatalysts in energy conversion processes, including oxygen reduction reactions. By incorporating leather waste into sustainable energy technologies, the industry can reduce its environmental footprint and contribute to the principles of a circular economy. The repurposing of leather waste not only provides a viable solution for waste reduction but also supports the advancement of renewable energy solutions, fostering both innovation and sustainability in the leather industry.</p>