The eight-foot metal robot accompanies Klaatu, a visitor to Earth from a distant planet, aboard a flying saucer. He does not speak, but uses a beam weapon projected from beneath a visor to vaporize weapons and obstacles. Klaatu describes him as being part of an interstellar police force. He announces that the people of the universe constructed numerous robots like Gort and gave them irrevocable powers to respond to violent actions in order to "preserve the peace." He goes on to say that "There's no limit to what Gort could do. He could destroy the Earth."

Gort...Klaatu barada nikto. Gort is a large "seamless" robot that appears to be constructed from a single piece of "flexible metal". He was portrayed by 7'-7" tall actor Lock Martin wearing a thick foam-rubber suit designed and built by Addison Hehr. Two suits were created, fastened alternately from the front or back so that the robot could appear seamless depending on the camera angle. Another fiberglass statue of Gort was used for close-ups of him firing his beam weapon or when the scene did not call for him to move. In order to maximize the height of the robot, the costume was made with lifts in the boots and was designed so that the figure's helmet stands nearly a foot above the top of Martin's head. Prisms were employed so that Martin could see through the costume's visor and air holes were provided under the robot's chin.

Gort...Klaatu barada nikto...During most of the film, Gort remains motionless in front of the saucer, which rests on the National Mall in central Washington D. C. while scientists and military researchers examine him. At one point Klaatu communicates with him using signals from a flashlight. He also responds to spoken commands, including the famous line "Gort...Klaatu barada nikto", spoken by Patricia Neal's character towards the end of the film.