He fought in the Aiel War, but is a bit on the plump side now. He has a pink face and is balding.
He has known Thom Merrilin for many years, since the time when Thom was court-bard to Queen Morgase. It was this long-standing friendship that leads him to give aid to Rand al'Thor and Mat Cauthon when they arrive in Caemlyn after Thom was presumed dead helping them escape a Myrddraal in Whitebridge. Mat and Rand stay in an attic room while waiting for Moiraine Damodred and the rest of their party to reach Caemlyn.
Mat and Thom stay in The Queen's Blessing before beginning their journey to Tear. Thom asks Gill to start rumors about Lord Gaebril, that will hopefully reach Morgase's ears. Gill agrees saying that he will pretend it is one of the bad dreams he has been having.
Master Gill, Lamgwin Dorn, and Breane Taborwin accompany Queen Morgase, Lini Eltring, and Martyn Tallanvor when they flee Caemlyn. They arrive in Amadicia and are held captive in the Fortress of the Light by Pedron Niall. He manages to escape with Morgase and the rest of her crew with the help of Sebban Balwer.
While traveling in Ghealdan he and his group are saved by Perrin Aybara when they are attacked by the Prophet's men. They then join with Perrin's army and become attendants under Faile Bashere. Perrin recognizes Gill, having met him before. Gill becomes Perrin's shambayan.
Perrin sends him north just before the attack on the Shaido in Malden with the intention of catching up with him afterwards. His force is intercepted by the Children of the Light, who keep them captive. He is returned to Perrin's army after Perrin's trial. He finally leaves Perrin's camp to continue serving Morgase, when her identity is revealed to everyone.