Gary Gilmore was executed on January 17, 1977, at 8:07 a.m. by firing squad at Utah State Prison in Draper, Utah. The night before, Gilmore had requested an all-night gathering of friends and family at the prison mess hall. On the evening before his execution, he was served a last meal of steak, potatoes, milk and coffee but consumed only the milk and coffee. His uncle, Vern Damico, who attended the gathering, later claimed to have smuggled in three small, 50ml Jack Daniel's whiskey bottles which Gilmore supposedly consumed.

In the morning at the time of execution, Gilmore was transported to an abandoned cannery behind the prison, which served as its death house. He was strapped to a chair, with a wall of sandbags placed behind him to trap the bullets. Five gunmen, local police officers, stood concealed behind a curtain with five small holes, through which they aimed their rifles. When asked for any last words, Gilmore simply replied, "Let's do it."

Prison officials stated that the firing squad comprised four men with live rounds, and one with a blank, so that the shooters could not be certain as to who fired the fatal shots. However, upon inspecting the clothes worn by his brother Gary at his execution, Mikal Gilmore noted five holes in the shirt. According to his memoir Shot in the Heart, "the state of Utah, apparently, had taken no chances on the morning that it put my brother to death."

The following day, his ashes were scattered from an airplane over Spanish Fork, Utah.