It was first formed during the era of the Clone Wars where it battled against the assaults from the Confederacy of Independent Systems. However, following the creation of the New Order, the Resistance fought against the machinations of the Galactic Empire. This was because of the Imperial practice of capturing Wookiees in order to use them for slave labor and at its peak, the Kashyyyk Resistance desperately fought for its survival as well as freeing their people from a reign of tyranny. Though lacking a formal organization, the Resistance was formed when a band of Wookiees decided to stand up against their oppressors leading to the formation of cells with defined leaders of this small groups.
At times, these separate cells do decide to merge together to form a larger group though this act was often dangerous as the Empire was ruthless and zealous in its attempts at exterminating any signs of rebellious movements on their slave worlds. This prevented the Kashyyyk Resistance from being an organized group and forced them to maintain only sporadic contact with another to the point that many of its members were unaware that there were other resistance fighters around the world. On rare occasions, the multiple group of Wookiee Freedom Fighters formed together in a joint operation to strike a blow against the Empire but the Imperial response was swift and brutal.
During certain moments, the Kashyyyk Resistance was aided by outside elements such as the Rebel Alliance which saw the group benefiting from the resources of another organization but maintained the ferocity as well as local knowledge of the Wookiees. Local traders and merchants were known to also support the Wookiee's by helping them to evacuvate their families or to engage Imperial slave transports.
The Resistance was mostly formed from Wookiee's who had broken the shackles of slavery and managed to flee into the jungles of their homeworld. Hiding within the dense jungles of Kashyyyk, they used the trees to move about undetected and strike from these positions. After the attack, they quickly retreated back into the trees and any Imperial pursuit normally suffered a high rate of casualties. The organization had a single objective which was freeing their people from slavery and removing the Empire's presence from their homeworld. This sees them sabotaging Imperial operations and attempting to increase their numbers by striking targets where their captive kin were imprisoned. Sometimes, these freed Wookiee's were encouraged to escape off-world and the Resistance conducted actions to ensure that as many of their kind were able to escape to other planets.
Though Wookiee's were known for their great strength, the Kashyyyk Resistance was known to use advanced equipment to support their goals. This included the use of traditional bowcasters, devastating grenade launchers and the actions of recon droids. A linked series of comlinks were used to remotely use the recon droids that were used to scout nearby areas and were equipped with explosive charges to eliminate hidden targets. They were also known to had retrofitted Oevvaor jet catamaran so that they could be used to fight off Imperial gunships or landers.