Lyonie was a Gungan male who held the position of boss within the Gungan High Council throughout the Clone Wars. When the Galactic Republic required assistance against the Confederacy of Independent Systems on the planet of Mon Cala, Jar Jar Binks, the Gungan Junior Representative, convinced Lyonie to dispatch Gungan warriors to support the Republic during the battle there.
Later, Lyonie was manipulated by the Separatists when Rish Loo, one of his advisors, provided him with a hypnotic device that was disguised as a necklace. Loo, a Separatist supporter, subsequently influenced Lyonie to announce a declaration of war against the Naboo people. This strange behavior caught the eye of Senator Padmé Amidala and Jedi Knight Anakin Skywalker, who observed Lyonie delivering a speech before he destroyed the necklace, thus liberating the Boss from Loo's control.
Following this, Lyonie confronted Loo, who attempted to regain control of the Boss. However, during a struggle that ensued after Skywalker entered the room, Loo was stabbed. Loo then fled, falsely announcing Lyonie's death and seizing control of a Gungan assault on the city of Theed. While Lyonie recuperated from his injuries, Binks impersonated the Boss and successfully prevented the attack.