Tal Hesz co-led the Jabiimi resistance with Nolan Gillmunn throughout the duration of the Galactic Civil War.
Despite his commitment to liberating his planet from Imperial oppression, Hesz harbored distrust toward the Rebel Alliance. Hesz became enraged when Gillmunn escorted a Rebel diplomatic delegation to Jabiim for discussions with the resistance. Upon discovering that Luke Skywalker, a member of the Rebel team, was a target of Darth Vader, Hesz pledged to hand over the Rebel in exchange for a cessation of conflict on Jabiim. His scheme failed, and he was only able to deliver the rebel mathematician Jorin Sol to Lord Vader. Vader was infuriated by this and the escape of Skywalker and the rest of the rebels, leading him to command the enslavement of Jabiim's inhabitants and an orbital bombardment that reduced the planet to ruins.
This occurrence deeply impacted Hesz, motivating him to embark on a personal quest to locate Sol and his fellow Jabiimi. Following weeks of searching, an informant directed him toward Kalist VI. He stole an Imperial shuttle, disguised himself as a Stormtrooper, and set course for the planet. Hesz's arrival coincided with the appearance of a Rebel fleet, which came to rescue his people and Jorin Sol. After the conflict on Kalist VI concluded, Hesz's true identity was revealed, resulting in his capture by the Empire.