When he was a child, his mother left his father Roger Sharpe. He was raised by his paternal grandmother, who considered his mother "a real floozy." He served in the Motor Pool during the Gulf War and believed that the government had conducted experiments on him and his fellow soldiers. He had a friend named Chuck, who was a conspiracy theorist.
In 2002, he worked at Glenwood Market. When Colonel Jack O'Neill stopped there for gas, he was affected by the Interdimensional visibility device. He tried to escape the quarantine set up by Stargate Command after seeing the insects, but was persuaded by O'Neill that the insects were aliens from Melmac and he was treated. This prevented mass panic.(SG1: "Sight Unseen")