Garn Stewer was a male human who held the position of chief technician for the starship maintenance team stationed at the Alliance to Restore the Republic's base located on the moon of Yavin 4. His responsibilities included the upkeep of the Alliance's fleet of T-65 X-wing starfighters, BTL-A4 Y-wing assault starfighter/bombers, and UT-60D U-wing starfighter/support crafts, and Stewer worked to foster a cooperative atmosphere between the rebel pilots and the ground personnel at the base. The head technician frequently pleaded, though in vain, with the pilots to avoid damaging "his" starfighters; however, these complaints were just playful banter between Stewer, his team, and the pilots.
In the year 0 BBY, he was present within the base's hangar when the criminal known as Jyn Erso was escorted in to participate in Operation Fracture. Sometime between 1 ABY and 3 ABY, Stewer took on the role of hangar chief on the Rebel vessel Home One. He was in the process of repairing Ibti Myrak's T-65B X-wing starfighter when she attempted to board it during an emergency situation. This resulted in a heated exchange between the pilot and Admiral [Gial Ackbar](/article/gial_ackbar], prompting Stewer to intervene. However, Myrak pushed him aside and departed in her fighter. Stewer then informed the admiral that she had entered hyperspace in order to rescue Rogue Squadron from the ambush taking place in the Valo system. Upon their return, Stewer was instrumental in the arrest of the double agent Lyle Kullan.
At some point, the chief became a father to Garn Stewer, Jr., who went on to serve the Resistance as an A-wing pilot.
Stewar's physical features included brown hair and [eyes](/article/eye], complemented by a fair complexion. While working at the base, he was typically seen wearing a synthetic boilersuit and a modified version of the standard Alliance service helmet equipped with a comlink but lacking a visor.
Garn Stewer's initial appearance was in the film Rogue One: A Star Wars Story, which premiered in North America on December 16, 2016. Although Stewer was not explicitly identified within the film itself, his name was later revealed in the reference book titled Star Wars: Rogue One: The Ultimate Visual Guide, authored by Pablo Hidalgo and released in conjunction with the movie.