Gary "Eggsy" Unwin is an agent with the Kingsman agency.
The Kingsman is a part of the British intelligence community. Some say it is just a division of MI6 while others indicate it is its own branch, taking on the jobs that are far too tricky for the mainstream groups to handle. To the agents who call themselves a Kingsman, it is more than a job; it is a way of life. To be a Kingsman is to be able to step into any spot of trouble with cool and panache and resolve the matter with the greatest of grace and style. Cool takes its cue from a Kingsman.
There are, truth be told, two versions of Eggsy, one in the original adventures told in graphic novel format and one told in celluloid and later recounted in comic books. Even the last name of Eggsy, as he is most commonly known, is different. One version has it being London and the other being Unwin. One has Eggsy being the nephew of the man who would train him to be a Kingsman and the other says he was the son of the fellow agent who saved his mentor's life. Which of these is true is really unimportant except to purists and it is unlikely to be any real agreement.
So we look at the basic concept of Eggsy and just enjoy his adventures.
Eggsy, whether he be related to his recruiter/trainer, is a teenaged almost-a-man who is increasingly prone to getting into mischief. Without a father figure, since his dad died in the line of duty as a Kingsman, Eggsy was left without someone to box his ears when they really needed a good thumpin'. There is no doubt that anyone having the misfortune to deal with him, other than his mates, would consider Eggsy nothing but a hooligan.
But he has talents, as his soon to be teacher sees. "Potential" is the way it is put. Others might call him a diamond in the rough but boy does he need a lot of polishing.