During the Clone Wars, Kulish accompanied Foxfire Squadron to Ongary IX, after the Ividal Sector Forces were called upon by the Republic to contribute fighter squadrons to participate in a counterattack against the Confederacy of Independent Systems. During the engagement, the Headhunters of Foxfire Squadron were deployed as bombers to fire burrowing plasma charges against Separatist forces entrenched in the planet's mines. However, they encountered difficulties when it was found that the extreme brightness of the burrowing plasma charges' explosions would completely polarize the visors of flight helmets and scramble head-up displays. This resulted in two casualties within Foxfire Squadron, Jens and Rafana, in two bombing runs. For a third bombing run, the squadron's helmets were retrofitted with plastoid blast shields, which were designed to be flipped down when the missile was launched to protect the eyes from the explosion and be raised again once the flash had dissipated.
Foxfire Squadron fought through a screen of Vulture droid starfighters before flying nap-of-the-earth to attack the mine. While firing his warheads, Kulish lowered the blast shield on his helmet to protect his eyes from the flash caused by the detonation of the explosives. The attack was a success, but after the explosion had passed Kulish's blast shield jammed and he almost crashed into a mountain before he was able to remove his helmet.
In the aftermath of the battle, Foxfire Squadron were sent to load their Headhunters onto a Republic Venator-class Star Destroyer for passage back to Ividal. Kulish declined to accompany them because after his experience during the battle he wasn't keen to fly his fighter again and he quit his job. Kulish instead gained passage off-world with the Republic Group agents Tobb Jadak and Reeze Duurmun aboard the YT-1300 light freighter Stellar Envoy.
During the journey, Kulish took his helmet out to help explain to the two agents the reason why he quit. Kulish subsequently disembarked at Denon and accidentally left his helmet behind, though he did not regret the loss.
Decade later, during the Galactic Civil War, the prospective Jedi Luke Skywalker used Kulish's helmet while training against remotes aboard the Stellar Envoy–then known as the Millennium Falcon.
Jorn Kulish was first mentioned in the StarWars.com article Star Wars: The Essential Guide to Warfare: Author's Cut, Part 10: The Rise of the Empire, an article in series by Jason Fry and Paul R. Urquhart that published content written for the reference book The Essential Guide to Warfare that did not make the final cut. The cut-content consisted of a portion of text written from an in-universe perspective by Jorn Kulish on his experiences during the battle over Ongary IX and served to provide a backstory for the helmet worn by Luke Skywalker aboard the Millennium Falcon during the events of the film Star Wars: Episode IV A New Hope.