Friction Stir Welding (FSW) is developed as a game-changing solid-state joining technique, influencing manufacturing and engineering in significant ways. This paper presents a review of FSW, covering its current status, working procedure, and critical process parameters along with complexities associated with FSW. Also the paper included the core mechanism behind FSW, optimized tool design, and the significances of the FSW input variables that affect the joint quality. Additionally, the paper showcases modern applications of FSW and discusses existing barriers, pointing to future directions for improving FSW’s efficiency, dependability, and flexibility for broader use in industry. FSW is unique because it can create strong, flawless joints without melting the base materials, which makes it perfect for metals that are heat-sensitive and lightweight. The article goes into details about how process variables that affect weld integrity, including tool spindle speed, feed rate, longitudinal force, and tool shape, are crucial. The impact of tool design on material flow and heat generation is examined rigorously. Microstructural variations in the weld zone, tool wear, and temperature distribution are among the complications covered. The study also emphasizes the growing use of FSW in sectors like shipbuilding, automotive, and aerospace. It ends by describing research prospects to get beyond existing constraints and improve FSW's flexibility in a range of workplace environments.