Adam Hayes is an agent with Treadstone.
Operation Treadstone is a project inside the CIA which over the years has turned into its own department (my term). One of the first operatives in this now quite infamous project was but there have been several others both at the same time as Bourne and then later. Hayes is one of them.
The existence of Treadstone is, understandably a highly compartmentalized ultra secret within the intelligence community. While in some regard there is Congressional oversight of this group, the exact extent of its operation and its activities is hidden even from its overseers. Most in the Agency have never known of it and most of those who did learn about it have long thought it either an Agency myth or something discontinued long ago.
The purpose of Treadstone was to produce super-soldiers. It selected highly skilled and motivated members of the U.S. Armed Forces and, using chemical enhancers as well as psychological manipulation, transformed these individuals into the absolute utmost in killing machines. The idea was to then be able to send an individual agent into extremely dangerous environments with the mission of taking out a key target and have a hope of actual success.
As mentioned, Hayes is one of those agents so treated by Treadstone. As it is put when we first meet him, he is "just the instrument - a man conditioned to kill without hesitation".
"The first time Hayes heard about Treadstone, he was in Afghanistan. Three months into a six-month tour and he'd already lost two men. That's when things started to go sideways". His commanding officer was worried about his mental condition and sent him to Bagram to meet with a psychiatrist, or so they were told. In fact it was a recruiter for Treadstone and Hayes's life would never be the same.
As readers of the Bourne adventures and viewers of the movies are well aware of, Treadstone turns operatives into incredibly capable operatives but to a man that enhancement comes with a tremendous cost. Hayes would reflect that he "could handle anything they threw at him. He didn't mind the pain that came with the behavior modification and genetic reprogramming. It was what happened after that he couldn't handle. Which was why he was in Washington (when we first meet him) and his wife, Annabelle, and their two-year-old son, Jack, were living halfway across the country."