Harvey Bennett is an agent with the Civilian Special Operations.
Agent is probably not the best word. It is likely more accurate to say he is a member of the CSO, which he is, or rather will be once it is established.
When we first meet him, he is a park ranger in Yellowstone and enjoying it a lot. It mostly involved solitude and being outdoors with nature surrounding him instead of buildings and lots of people. It is not that he is anti-social but more that he is happier when not needing to be overly social. He has been a ranger for some time and it suits him and he would not have chosen to give it up if life and circumstances did not push the issue. What he gets pushed eventually to is the CSO.
To understand more about the CSO, it is necessary to know more about Mr. E. That is the only name I have found for the man so far and apparently I am not the only one in the dark about him as most of the people who work for him also know next to nothing. Mr. E is a very, very wealthy man who, being very paranoid, has a major desire for anonymity, hence not using his real name. Most of his dealings seem to be via video chat and what the people viewing it see is a very posh, expensive interior and the mystery man himself.
As for the CSO, Mr. E. explains when he first presents the info to Bennett and friends, "I was recently approached by a contingent of representatives from each branch of the United States Armed Forces to discuss the possibility of leading a project they're calling CSO, or 'Civilian Special Operations'." The idea was to put together a team of civilian experts "who possess the knowledge and training to accompany select members of special force units to accomplish missions that are considered taboo by the U.S. government". Further, "these missions are not expected to be militaristic in nature, which is specifically why it was decided men and women from the civilian sector should make up the majority of its membership".
So, from being a "leave me alone" park ranger to a member of a specialized team of civilians heading into extremely volatile and unknown situations, Bennett's life takes quite a shift.