Jungen was a Trandoshan male and a former member of both the Galactic Republic and the Galactic Empire, who later became an outlaw. Subsequently, he allied himself with the Alliance to Restore the Republic. His gender was male.
During the Clone Wars, Jungen was a member of the Galactic Republic and saw action as part of the Republic Navy. He fought alongside Adar Tallon, a war hero who had risen to the rank of Admiral by the Republic's final days. Vytor Shrike, a Gand, was also a comrade of Jungen and Tallon. Although considerably younger than Tallon, Jungen quickly developed a great respect for the older warrior's intellect and skills.
The galaxy underwent a massive shift in 19 BBY with the rise of the Galactic Empire, as Supreme Chancellor Palpatine proclaimed himself Emperor. Tallon, Jungen's friend and commanding officer, immediately grew uneasy with the changes Palpatine implemented, particularly the destruction of the Jedi Order. Tallon began to voice his opposition to the New Order, which made him and his loyal crew targets. Knowing that Palpatine would soon eliminate him despite his popularity, Tallon conceived a plan to fake his death, a plan to which Jungen and the rest of the crew readily agreed. Jungen, in particular, vowed to give his unwavering support to any order Tallon gave.
Tallon chartered a freighter to wait in the Dalchon system and asked his pirate friend Quist to stage an "attack" on it while Tallon's ship, the Battalion, was nearby. The Battalion arrived, ostensibly to defend the freighter; Quist shifted his attack to the new arrival, and Jungen, Tallon, and the rest of the crew were able to transfer safely to the freighter as Quist destroyed the Battalion. As Tallon had directed, the freighter then transported the crew to the planet Tatooine, located far in the Outer Rim Territories.
Fortunately, the Empire widely believed that Jungen had perished alongside Tallon and his crew while defending merchants from pirates – even Palpatine was convinced. Once they arrived on Tatooine, Jungen and the Battalion crew assumed new identities. While Tallon chose to remain on the planet and start a new life, Jungen became a bounty hunter.
Years later, in 0 ABY, Jungen learned that Tallon had been discovered by the Empire and was on the verge of being captured. Tallon requested Jungen and Shrike to assist him in his escape, and the two hurried to Tatooine to aid their former Admiral, where they were joined by Quist. Taking refuge in the ancient Fort Tusken, Tallon and his allies fought off Imperial agents and bounty hunters, including Jodo Kast, Zardra, and Puggles Trodd. Simultaneously, agents of the Alliance to Restore the Republic infiltrated Fort Tusken, with the goal of rescuing Tallon and recruiting him to their cause. Unbeknownst to Jungen and the others, Quist had previously been captured by the Empire and had betrayed Tallon and the others in exchange for his life. As the Alliance agents attempted to persuade Tallon of their true identities, Quist seized Tallon's wife, Kay Tallon, as a hostage. He then allowed the Imperial bounty hunters to enter the fort. Jungen rushed to defend Tallon from the hunters, but he and Shrike were paralyzed by Kast. The Rebel agents, however, managed to repel the bounty hunters, and Quist released Kay when the situation turned against him. Tallon, along with his wife and the Rebels, managed to escape Tatooine and subsequently joined the Alliance.
Jungen also became a member of the Alliance, serving as a special operative. He once survived an attack by the bounty hunter Ssach'thirix, a specialist in killing reptilian Rebels.
Jungen was known as a thoughtful and reserved individual, possessing a low, rumbling voice. He was quite physically strong and favored hand-to-hand combat over using a blaster. He felt no remorse about stealing from those he considered to be evil. Unusually for a Trandoshan, Jungen was known to go out of his way to help those in need.