Robert William Gary Moore was a Northern Irish musician. Over the course of his career, he played in various groups and performed a range of music including blues, blues rock, hard rock, heavy metal and jazz fusion.

Robert William Gary Moore was born in Belfast on 4 April 1952, the son of Winnie, a housewife, and Robert Moore, a promoter who ran the Queen's Hall ballroom in Holywood. He grew up near Belfast's Stormont Estate with four siblings. He credited his father for getting him started in music. When Moore was six years old, his father invited him onstage to sing "Sugartime" with a showband at an event he had organised, which first sparked his interest in music. His father bought him his first guitar, a second-hand Framus acoustic, when Moore was 10 years old.

In the mid-1970s, Moore was involved in a bar fight which left him with facial scars. According to Eric Bell, Moore was with his girlfriend at Dingwalls when two men "started mouthing about Gary's girlfriend what they'd like to do to her". After Moore confronted them about it, one of the men smashed a bottle on the bar and slashed Moore's face with it. This had a profound effect on him. Bell said, "It did change him. A lot of that pent-up anger and emotion would come out in his playing. And it came out in other ways too. It must be a hard thing to come back from something like that." During the 1980s, he would hide his scars in photographs and videos by looking down or being framed from a distance.