Joe 'Owl' Bolt is a freelance agent.
He is an assassin for hire.
He takes those assignments he feels he should and carries them out which means invariably somebody dies. He is especially particular about which missions he will accept and which he will pass on. His clientele was varied and often changing. The person seeking his elimination services might be an actual person or "a cutout for an intelligence agency. Or a private security company". As I said, it varied.
The job offers come to him via his Broker, a woman that knew him only by his covername of "Owl". "She didn't know his real name. She had never met him. Had never even seen a photo of him. She performed three services for Joe. Vetted clients. Collected payment. Paid Joe". Very straight-forward. Bolt enjoyed this "layer of anonymity" because in his mind, "nobody could be trusted".
We are told immediately that Bolt "was a patriot. He loved America. He never acted against American interests". That does not mean that he would not accept an assignment that took place in the States or that he would not eliminate an American citizen. What might be harmful to America was his determination.
Interestingly, being an assassin might be his primary source of income but on the record he has a totally different line of work. He is a professor in government studies at Georgetown University, the same college from which he earned his PhD. "He loved the university. The atmosphere. The people."
His explanation for why he, an educated man with a highly respectable and envious position in life chose to spend time as a paid killer is simple. "Joe needed the game [of being a killer]. For intrinsic reasons. But also for an extrinsic reason. Money. He made good money as a professor. But not good enough. He like expensive things. Artifacts. Clothes. Wine. He liked expensive vacations. Battlefield tours in France. Safari adventures in Kenya. Train rides in Japan."