Hailing from Kashyyyk, Gluk Gluk was born in the city of Rwookrrorro to Attichitcuk and a female Wookiee 180 years before the Clone Wars. Gluk Gluk is the second son of Attichitcuk and his mate, the first son being none other than Chewbacca. During their lives, Gluk Gluk and Chewbacca explored Kashyyyk, including the wildest reaches of its forests and from one pole to another.

During the Clone Wars, Gluk Gluk and his older brother served as combat engineers while other Wookiee soldiers led the charge in battle. In 20 BBY, Gluk Gluk narrowly escaped capture by a Trandoshan hunting guild, but alas Chewbacca was caught and was taken to Island Four on Wasskah to be the hunting guild's prey. To rescue his brother, Gluk Gluk joined a Wookiee relief force led by General Tarfful--who had received a distress transmission from Chewbacca soon after Chewbacca's capture. Gluk Gluk and General Tarfful--aided by bounty hunters Sugi and Seripas--successfully released Chewbacca from bondage. General Tarfful later frocked both Gluk Gluk and Chewbacca to the rank of Lieutenant secondary to their display of valiance amid bondage, capture, and rescue while also working to free other prisoners of the Trandoshan hunting guild.

Lieutenants Gluk Gluk and Chewbacca were later both major players within the Battle of Kashyyyk, overseeing the confrontation between the Grand Army of the Republic and the invasion of the Separatist Droid Army alongside General Tarfful, Jedi General Yoda, and Jedi Master Luminara Unduli. Following the implementation of Order 66, Gluk Gluk, Chewbacca, and Tarfful witnessed the assassination attempt on Yoda's life by Commander Gree and his aide. Gluk Gluk and Chewbacca helped Yoda elude the clone troopers and escape from Kashyyyk.

Following the reorganization of the Republic into the Galactic Empire, Gluk Gluk and Chewbacca saw their Wookiee people sent to work as slaves, miners, or made to serve as science experiments. It was not long until Gluk Gluk and Chewbacca were again captured by Trandoshan slavers and were forced into slavery. Together, they cut wroshyr trees to feed the Imperial Army. The two temporarily escaped but were betrayed by a greedy Kowakian monkey-lizard bounty hunter. Whilst aboard a prison train on Kethmandi, Chewbacca had the opportunity to escape captivity but sacrificed his own freedom to save Gluk Gluk.

Gluk Gluk took refuge at the planet Hoth and refined his mechanical skills via working for the Rebel Cause. Together, with other engineers of the Cause, he was able to become a proficient mechanic and planned to travel to Vandor to obtain a train car of coaxium. Little did he know that Chewbacca was also trying to obtain this same train car with Han Solo. Although both parties were initially thwarted by the efforts of Enfys Nest and the Cloud-Riders, Solo's quick thinking allowed him to trick the Cloud-Riders into obtaining fake coaxium, whereas Chewbacca and Solo were able to escape with the real coaxium. This coaxium was later entrusted to Nest, who intended to use it to form a rebellion against the Empire. Thus, Chewbacca and Gluk Gluk worked together on this mission without the knowledge of the other's assistance.

Gluk Gluk later escaped a series of assassinations from several bounty hunters, including Zuckuss and 4-LOM. However, during his escape from 4-LOM, Gluk Gluk was later captured for the third time by Trandoshan slavers and was forced into the back of a truck with a few other peculiar prisoners...