Ian Edgerton

Ian Edgerton (portrayed by Lou Diamond Phillips) is a recurring character who has appeared in five out of the six seasons. He is an agent who has assisted Don and his team in various cases. He is the FBI's best sniper, as well as being the fourth best shot in the United States. He is also a top tracker, and has the luxury of choosing his own cases. Ian also works as a sniper instructor at Quantico when he is not working a case in the field.

According to Colby, Ian did a tour of duty in Afghanistan and was highly respected by other military men deployed there. Colby stated that although it was obvious from the aftermath that Ian had been involved in an operation, "you never saw him". Ian is highly intelligent and loves his work.

During their first encounters, Ian and Charlie clashed: Charlie did not believe in using guns to solve problems and disdained Ian's dispassion about killing, while Ian believed Charlie's mathematic approach was too academic for real cases and his scientific viewpoint made his objections to Ian's attitude hypocritical. He even went so far in their early acquaintance as to call Charlie's math "voodoo". Despite their early rancor, however, the pair have come to a mutual respect for their different expertises and even a kind of friendship.

Ian has apparently known Don since before the series began, likely dating to Don's tenure as a tactical instructor at Quantico. He backed Don up to their superiors regarding Don taking the Crystal Hoyle kill-shot, which took place in "Two Daughters" (season 3 episode 2). Ian referenced this when talking with Don in "Pandora's Box" (season 3 episode 19).

It is heavily implied in "Two Daughters" and "Pandora's Box" that Ian used interrogation techniques which included physical force and borderline torture to get information out of Buck Winters, Crystal Hoyle's teenage accomplice. It is also implied that Don has seen or heard of Ian using such techniques before. Buck mentions "a few bruises and broken bones" in "Arrow of Time" (season 5 episode 11). Given that Ian's superiors were more concerned with Don shooting Crystal Hoyle than Ian's interrogation methods, it is likely that Ian will not be disciplined or will only be disciplined lightly over this incident.

With the kill shot through the cab windows of a pickup truck, executed in "Pandora's Box", Ian hopes to be moved up to third-best shot in the U.S.

Edgerton did not appear in season four, but returned in the premiere and finale for season five.