Gregg was sentenced to 18 years in prison; however, he only served nine years before he was released in 1993. When asked by the BBC in prison if he regretted anything about the shooting, his reply was, "Only that I didn't succeed." Following his release from prison, Gregg returned to Rathcoole, where he again became an important figure, taking a central role in the illegal drug trade, with his Rathcoole stronghold a centre of narcotics. Sometime after the Combined Loyalist Military Command of 1994 he succeeded Joe English, who had emerged as a leading figure in the Ulster Democratic Party, as brigadier of the South-East Antrim UDA. Under Gregg the South-East Antrim Brigade were prepared to ignore the terms of the loyalist ceasefire, such as on 25 April 1997 when he dispatched a five-man team to Carrickfergus to set fire to a Catholic church in retaliation for a similar attack on a Protestant church in East Belfast (this earlier attack had actually been organised by dissident loyalists seeking to provoke the UDA into returning to violence). Gregg's fearsome reputation earned him the nickname "the Reaper" and he bore a tattoo of the Grim Reaper on his back as a tribute. Gregg played the bass drum in the UDA-affiliated flute band Cloughfern Young Conquerors, a loyalist flute band which police claimed regularly caused trouble at Orange Order parades. In late August 1997 this band was one of a number of similar flute bands to travel to Derry for the annual Apprentice Boys of Derry march through the city centre. As the band prepared to take the train home that evening they met members of the Shankill Protestant Boys, another band in town for the parade that was affiliated to the Ulster Volunteer Force (UVF). Brawls between the two had been frequent and tensions had been growing between the UDA and UVF leading to a drink-fuelled pitched battle between the two groups at the train station. During the course of the melee a Shankill Protestant Boys member managed to gouge out Gregg's eye, although it is also claimed that Gregg lost his eye due to a fight with republicans at the same parade. Along with Jackie McDonald and Billy McFarland, fellow brigadiers on the UDA's Inner Council, Gregg was lacking in enthusiasm for the Belfast Agreement when it appeared in 1998. Throughout 1999 his brigade continued to be active, undertaking a pipe bomb campaign against Catholic homes whilst on 12 May members of his brigade shot and wounded a Catholic builder in Carrickfergus under the cover name "Protestant Liberation Force".