Considered by many of his comrades to be an antagonist, Major Louis Ferretti, under the command of Colonel Jack O'Neill and General West, was one of the first to walk through the Stargate to Abydos when it was opened by Daniel Jackson.
Frequently succumbing to pessimism, he was intent on making Jackson suffer for lying about having the ability to reopen the gate from the Abydos side and get them home -- scattering Jackson's books across the desert terrain. Ferretti is thus inadvertently responsible for revealing the Abydonian population, as his mess caused Jackson to pursue a mastidge beast that led the team to a nomadic civilization. Ferretti was instrumental in fortifying the pyramid landing platform of Ra's mothership, giving Colonel O'Neill and Daniel Jackson time to complete their objectives.
He survived the Abydos mission and returned a year later to uncover a new Goa'uld threat led by Apophis. In the process he suffered severe injuries, but survived to deliver the gate coordinates that would allow SG-1 and SG-2 access to the world of Chulak.
Some time after the death of Major Charles Kawalsky, Ferretti was given command of the SG-2 field unit. Later in the same year he was in charge of an operation that would have led to the courts martial of SG-1, but the mission was cancelled when the Stargate could not make a lock on the address to which they had gated.
"Stargate" the Movie - Ferretti, one of O'Neill's most reliable officers, joins the first team to go through the Stargate to investigate possible threats to Earth.
Children of the Gods - Ferretti returns to Abydos do determine the whereabouts of a new alien threat that recently attacked Earth through the Stargate. He is severely wounded when Apophis's forces attack Abydos.
Within the Serpent's Grasp - Ferretti is ordered by General Hammond to retrieve SG-1 for courts martial, but is unable to commence the mission when the Stargate does not lock on the coordinates to which SG-1 gated.
Shades of Grey - With O'Neill off the team, Daniel speculates that General Hammond may assign Ferretti to replace him as the leader of SG-1 -- indicating that he is still in active duty at the S.G.C.