Jericho Quinn is an agent with the OSI
The U.S. Air Force Office of Special Investigations is tasked with providing, among other things, counter-intelligence operations in theaters in which their forces operate and that certainly includes Iraq and Afghanistan. One of their very best agents is Major Jericho Quinn.
Born and raised in Alaska, Quinn is a very intelligent and driven man who is smart enough to survive in both the civilized and not-so-humane worlds that war usually creates. He is particularly adept for the action in the Middle East. In addition to speaking perfect Arabic with the skill to mimic various dialects, his copper skin coloring, a genetic gift from his Apache grandmother, makes it far easier for him to blend in. With a beard as needed, dressed in a dishdasha, he can come and go more places than his colleagues.
The older of two brothers, Quinn earned a shot at the Air Force Academy and made the best of it, including becoming a Fulbright scholar. His love of languages and his skill at learning them, in addition to English, he speaks 4 natively and several more conversationally, made him a natural for recruitment by the OSI. His love of the action and his devotion to duty kept him there even though it cost him his marriage to Kimberly and took him away from his young daughter.
As the series begins, Quinn is out to save the lives of several servicemen captured by the enemy and targeted for execution. When he learns the location of one of the sites, he knows that time is of the essence but his superior wants to be in on the raid and orders him to stand down. He and a Marine gunnery sergeant disobey and save a couple of soldiers just as they were about to be killed.
This resulted in being brought up on charges but cooler and more experienced heads prevailed. Moreover, the fact that one of the rescued was the grandson of the head of National Intelligence, Winfield Palmer, brought Quinn and the Marine, a Cajun named Thibodaux, to that man's attention. Reviewing the service records of both men, he decide they were what he was seeking.
As Palmer explained, he had a lot of highly sophisticated tools at his disposal but sometimes the best tool was a simple hammer. Blunt, powerful, direct. Quinn and his friend were such men and though they would on paper remain in their previous positions, they would be on call when Palmer and the President needed.