Mechani-Kong first appeared in the ninth episode of The King Kong Show (the segment titled "Mechanikong") as one of several monsters in the series used by Dr. Hu to fight Kong.
Mechani-Kong was built by Dr. Hu to dig for Element X, a large core containing a natural abundance of nuclear power. However Mechani-Kong was not strong enough to dig out the element, as the robot's circuits were destroyed by magnetic waves. Dr. Hu then kidnaps the real Kong to dig for the element, placing him in a hypnotic trance. Kong eventually breaks out of his trance and swims to Tokyo, where he and Mechani-Kong fight atop Tokyo Tower. After a long battle, in which both of them nearly fall off the tower, Dr. Hu's associate Madame X rips out the robot's control cords, causing Mechani-Kong to malfunction. The robot falls to its destruction from the top of the tower, mirroring Kong's demise in the original film.
After abandoning a remake of King Kong vs. Godzilla in 1991, Toho attempted to produce a film called Godzilla vs. Mechani-Kong. However, though Toho had created the live-action Mechani-Kong, Turner demanded payment for using King Kong's image. The film was dropped in favor of Godzilla vs. King Ghidorah.
Aside from its great strength, Mechani-Kong possesses a dome on the top of its head which features a flashing light that can be used to blind or hypnotize its foes. Although not as agile as the real Kong, Mechani-Kong possesses greater endurance. It is later modified with attachments on its waist which it uses to carry multiple grenade-like explosives. He can also fire beams from his eyes.
Mechani-Kong inspired the creation of Mechagodzilla for Godzilla vs. Mechagodzilla.
Mechani-Kong also inspired the creation of an enemy character named 'Mecha Pong' from Capcom's 1989 arcade game Strider.
Akira Ifukube utilized a reworked version of Mechani-Kong's theme for Mechagodzilla in the Heisei film Godzilla vs. Mechagodzilla II.
In Godzilla: The Series, a monster appeared called Robot Yeti who is very similar to Mechani-Kong.
In The Grim Adventures Of Billy And Mandy episode "Giant Billy and Mandy All Out Attack" Mandy gets a robot named Mecha-gorillasaur in order to stop a gigantic humanoid fish hero version of Billy.