<p>Tribology and microstructure analysis play a vital role in defining the durability and performance of friction stir welded (FSWd) AA 6061. This research investigates the effect of in-process indirect cooling on tribological properties and the evolution of intermetallics in FSWd AA 6061. Indirect in-process cooling is employed with three different cooling media, i.e., air, water, and brine solution and their influence on microstructure and tribology was analysed. The microhardness of all the welded samples was also analysed. The microhardness in the stir zone of the water-cooled sample at 850 rpm tool rotational speed was closest to the base metal and improved by 29.17 % compared to the air-cooled sample. The results also indicate that indirect cooling improves microstructural and tribological properties with no formation of weld defects and oxides. The maximum wear rate was observed in the air-cooled sample at 20 N load and 150 °C temperature. Using water and brine solution cooling causes a reduction in wear rate by 88.5 % and 80.4 % respectively, at 20 N load and 150 °C temperature. The brine solution provides the maximum control over the highest temperature on the tool and fixture, and reduces it by 49.07 % and 40.5 % respectively, at 850 rpm tool rotational speed. This research provides valuable insight for optimising process parameters in advanced engineering applications, especially in the aerospace and marine industries.</p>