Leon was only twenty one during the events of RE2. After graduating from the police academy, he filed an application for assignment to the Raccoon City Police Department. He was able to avoid the fate of his new colleagues by pure chance after showing up late to work on his first day—the previous evening he had drunk himself unconscious in a motel in despair over his recent breakup with his girlfriend. This anecdote is at odds with his current "cool" image, and it can probably be attributed to the recklessness of his youth. The S in his name stands for Scott, but he rarely uses it.
The render below was created for RE2 (the image at the top was for Darkside Chronicles). While the early CG artwork may not have aged particularly well from a technical point of view, Leon's appeal can still be seen to this day.