Eeth Koth was born in the slums of Nar Shaddaa and orphaned at a young age. The Jedi were his saviors, and, as a result, he dedicated himself totally to the Jedi Order. Although Koth was four years old at the time, the Jedi felt he was too strong to leave behind. Eeth was well respected by his peers, and even participated in the Concodance of Fealty with fellow Master Mace Windu. Koth trained Sharad Hett as his Padawan until 47 BBY, when the young apprentice went missing. In 44 BBY, he fought in the Fift Battle of Qotile.
Koth was one of ten Jedi that volunteered to travel to Yinchorr with Mace Windu, to bring the Yinchorri to peace. He was teamed up with Adi Gallia, Tsui Choi and Theen Fida. Their group was dispatched to the planet Yitheeth. Their plan was to act as traders peddling plans for the new T-21 Hyper Partile Exchange Chamber. Koth noted that he had never heard of such an item. Adi had just made it up. Unfortunately for them, the plan went wrong and they were surrounded by a squad of Yinchorri warriors, led by Olmar Grahrk. The Jedi managed to defeat them, and they took Grahrk prisoner. Koth's group picked up the other two task forces with the only remaining Consular-class space cruiser, and proceeded to Yinhorr to rescue Master Windu's group. There was a fierce battle which cost the lives of three of the Jedi, including a Coucil member. In 27 BBY, during the Ashaar Khorda crisis, Koth personally safeguarded Alderaan.
Koth was sent with fellow Jedi Master Plo Koon to the planet of the Jin'ha to investigate the new warriors. When their ship crashed in the swamps they were both captured, however, Qui-Gon Jinn managed to free them.
After hearing reports that Qui-Gon's slayer Darth Maul might have been an Iridonian Zabrak, Koth conducted an investigation, but after some time he failed to discover the identity of the deceased Sith Lord.
Koth was part of the Jedi task force sent to rescue Obi-Wan Kenobi, Anakin Skywalker, and Padme Amidala. He participated in the Battle of Geonosis, during which he fought and survived the initial ambush in the arena. A LAAT/i gunship that rescued Koth, Sora Bulq, and Tardos Gon was brought down by Separatist fire. Koth and Bulq both survived the attack, while Gon did not.
In 22 BBY, Koth led a squad clone troopers in the Battle of Korriban to defend the besieged people of Korriban. The squad suffered numerous casualties.