Jake Webster is an agent with U.S. Intelligence.
The exact agency that Webster works for is not known. His immediately supervisor is Major Bernard Caldwell leading one to think it might be affiliated with the military but since Caldwell is definitely a bit beyond normal military age, he could easily be retired and working for a civilian agency.
Webster is described as an American expatriate living in Vienna and happily running a dining and drinking establishment with the very American title Jake's Bar and Grill. While it would be completely true that Webster obviously loves action and adventure, shown by the speed with which he leaps into any dangerous situation, we are quickly shown that his participation in the activities of his "bosses" is not all that voluntary.
It was seem that Caldwell personally or the Intelligence bureau Caldwell works with has some evidence held closely which could have a serious unpleasant affect on Webster resulting in his being arrested in his new home country of Austria. This means that the relationship between Webster and Caldwell is not always on the friendliest of terms. Forgetting his forced motivation, though, once Webster gets into a mission, he goes at it with tremendous gusto.
Webster is a single man likely in his late 30s. He is ruggedly handsome and, being in excellent physical shape, as attractive to the opposite sex that he routinely encounters as he is to them. This does open him up for a couple of "cases" which are not brought to him by Caldwell but by beautiful women in need of some assistance.