For many years, Solovar is the leader of Gorilla City, a hidden city of hyper-intelligent gorillas. Renowned for his wisdom and psychic powers, he is virtually unchallenged, except by the villainous Gorilla Grodd. This rivalry is so great that, after Solovar is captured by humans (playing dumb to keep his identity and origin secret), Grodd follows him to Central City to learn the secrets of Solovar’s force-of-mind powers.
The Flash helped the gorilla leader escape and became the first human to learn of the city’s existence, and its location. This leads to a rivalry between Grodd and the Flash, as well as an alliance between The Flash and Solovar.
Under Solovar’s guidance, Gorilla City is a technological utopia. Eventually, he decides his people can no longer use their science to hide from the human world. Believing that the world's ecological and political problems can't be solved by ignoring them, he opens his city's borders to the world and asks for membership in the United Nations. He advocates peace — among the gorillas and with humans — and is behind two diplomatic overtures to the human world. The second tour of the U.S., sadly, is cut short by his assassination by a lethal car bomb. While a mysterious group calling itself the Human Supremacy Movement takes credit for the act, it quickly made clear to the reader that Solovar's assassination at the hands of human racists is in fact a ruse concocted by the Simian Scarlet, a group of gorillas within Gorilla City seeking to overthrow the ruling council. (The manipulators are themselves manipulated by Gorilla Grodd.)
Solovar is briefly succeeded by his nephew, Ulgo. With tensions between humans and gorillas rising, the JLA is invited to Gorilla City to assist in a diplomatic mission, only to fall victim to an ambush. In the heat of battle, the gorilla army tests its new weapon on the heroes, a "gorillabomb" that transforms humans into gorillas. While the JLA retreat to their moonbase to find a cure, Prince Ulgo appears before the United Nations to formally declare war on the human race.
However, he promises, there will be no bloodshed in the battle, and he makes his point by detonating a gorillabomb in the auditorium. With the entire UN assembly transformed both mentally and physically into gorillas, the JLA act swiftly to minimize damage and loss of life. Alas, saving the delegates uses up their only chance to change back into humans, and so our transformed heroes must remain in their simian forms until they can find another way to return to normal.
Not that they're allowed much time to do that; as the Martian Manhunter telepathically learns, the gorillas are strategically targeting several places around the globe, including Themyscira (Wonder Woman's homeland), Atlantis (Aquaman's kingdom), Central City, Blüdhaven (a suburb of Batman's Gotham City), Metropolis (where Superman lives, one of the largest cities in the DC Universe), and low Earth orbit (Green Lantern's). The heroes split up and set out to neutralize the gorilla army, end the human-gorilla war, and find a way to return to normal.
Once the JLA have achieved their goals, Ulgo is later succeeded by Solovar's son, Nnamdi.