Andrew Keeton, is an agent of the CIA.
More specifically, Keeton is a part of Department 229, a small group of highly trained operatives tasked with rescuing civilians, i.e., those not actually in the espionage world, who have found themselves in danger from the Iron Curtain.
The year is 1964. Communism is a constant and growing threat with easily a third of Europe and most of Asia under the control of either the Soviet Union or Red China. Forays into South America and Africa are happening all the time. The need to pull key person out from under those totalitarian regimes seems never ending. Hence the need for a specialty group like 229. In keeping with the concept of coming to the rescue, this cadre of highly dedicated men and women have been given the nickname of 'the Cavalry'.
Keeton is one of those few. His codename within the organization is Orange. We learn early on that he is the "Cavalry's most tenured field agent, and he has the saves and the scars to prove it." He has learned the hard way that violence is a part of his profession and he had to become good at it early or succumb to it. He does not like taking a life but he knows it is often unavoidable. When early on a person he was rescuing comments, "I suspect you don't kill indiscriminately", Keeton responds, "No, but it's not always in self-defense, either." Rather chilling and telling.
But violent activity is not really where Keeton shone. "What made Keeton so good at being a spy and had kept him alive all these years was his ability to study the minutiae of human behavior: the trembles and tics of the muscles, the involuntary dilation of the pupils, the movement of the eyes, the inflection of an answer. It all added up to motive and intent, good or bad." Being able to read others, either those being helped or those causing the trouble, has kept Keeton alive in numerous very scary situations.