Jaga was voiced by Earl Hammond, who had voiced a number of other characters on the show, including the Thundercats archenemy Mumm-Ra.
As a Thundercat, he was friends with Grune the Destroyer. However Grune was an ambitious character with a lust for power, and he turned against the Thunderians and used his abilities for evil. Jaga was forced to fight his old friend. Defeating the other Thundercat, Jaga spared his life, and Grune was banished from Thundera.
Jaga later faced the mutant warlord Ratilla, who was trying to steal the Treasure of Thundera. Ratilla used his Sword of Plunn-Darr in combat with Jaga, who defeated him with help from the Sword of Omens. Fearing that further disaster would result, Jaga threw the Sword of Plunn-Darr into the deepest chasm on Thundera, unwittingly causing the planet to become unstable and eventually explode.
When it became clear that Thundera was going to explode, Jaga evacuated Thundera with the Thunderian nobles Panthro, Cheetara, Tygra, Wily-Kit, and Wily-Kat. Also along on the journey was young Lion-O, the young man who had just become Lord of the Thundercats.
Their spacecraft came under attack by the Mutants, a group of aliens seeking to capture the Sword of Omens. With help from the Sword of Omens the young Lion-O was able to drive off the Mutant forces, but the ship was badly damaged.
Realizing they would never reach their intended destination, Jaga and the Thundercats decided to make for a nearby habitable world. Jaga ordered the crew in to suspension capsules, but knowing due to his advanced age that he would not survive even in suspended animation. Jaga remained conscious and piloted the ship for as long as he could. After many years of piloting the ship, Jaga died at an extreme old age, but managed to activate the auto pilot before he passed away.
A short time later the Thunderian ship landed on the habitable planet - which the locals called Third Earth. Snarf and Lion-O were the first to awaken. After many years of cryo-sleep Lion-O's memories of the Sword of Omens were hazy until Jaga appeared to him in spirit form and reminded him of the sword. Lion-O was able to awaken the other Thundercats and drive off a Mutant attack.
Jaga would continue to appear to Lion-O when Lion-O needed advice. This included warning him that the Sword of Omens would not obey him should he try to use it for an evil act. When the Spirit of Grune the Destroyer launched an attack on the Thundercats, Lion-O summoned Jaga to engage his old friend in battle. Jaga was able to force Grune to leave the physical world.
- This version of Jaga also appears on the animated comedy Robot Chicken to inform Lion-O that the reason Cheetara and Wily-Kit were acting so strangely was because they were in heat and that the men had to stay away from the women. When the Thundercat males approach the women's quarters Jaga appealed to the men not to give in to their base desires before giving up and joining the men into barging in to the women's quarters.