Shouldn't this be on the JKII forum?
From the Graphic Novels:
Kyle Katarn is the only son of Morgan Katarn. Kyle's mother died when he was very young (though apparently not in childbirth).
Because the Katarns were hardscrabble farmers on Sulon (the moon of Sullust), Morgan scrimped and saved to allow his son to attend the Imperial University on Carida. Morgan wanted nothing but the best for his son, and was as good a father as anyone could hope for.
(Carida was best known for its military Academy [where Luke Skywalker once wanted to go], but they maintained a civillian campus that was as good as the University of Mrrlst, only cheaper.)
What Kyle didn't know was that his kind, gentle father was actually a key member of the Rebel Alliance. One of Morgan's closest friends had been a Jedi named Qu Rahn, and the two had worked together to locate the Hidden Valley of the Jedi on Rusaan (though Rahn was careful not to find out the coordinates; knowing that they'd be safer with Morgan). Morgan ran a sort of "Underground Railroad," helping enemies of the Empire to get to a Rebel "Safeworld" colony (serendipitously located on Rusaan).
Eventually, the Empire/Inquisitor Jerec found out about Morgan's activities, and that he knew the Valley's location (see JK Intro Cutscene).
A covert Imperial commando mission attacked several farms (so the attack on the Katarn homestead wouldn't stand out), and abducted Morgan Katarn. After interrogating him, Jerec cut of Morgan's head, and let Maw put it on a pike outside Barons Hed.
The series of attacks/atrocities were blamed on Rebels, and when Kyle found out about his father's brutal death, he transferred into Carida's military campus (rare, but not unheard of) and became a stormtrooper.
Kyle's final mission as a cadet was the destruction of a Rebel technical outpost (Kyle was commanding the mission) in an asteroid field. During the invasion, his gaze locked with that of an exotically beautiful young woman --love at first sight.
The mission ended up FUBARed, and many of the Rebel prisoners escaped.
It was no fault of his, and Kyle graduated with honours (the grad ceremony was overseen by Inquisitor Jerec himself, and Kyle earned personal praise and "condolences" from the miralucan warror).
Kyle (and most of his friends) had shore leave before their first tour of duty, and they went on a cruise. Aboard the spaceliner, Kyle was shocked to once again lock eyes with the girl from the Rebel outpost. He followed her to the lower decks and was promptly captured by her partner, a large and nasty human. The girl's name was Jan Ors.
Eventually, Jan showed him footage of what had really
happened on Sulon, and once he was convinced of the Empire's duplicity, Kyle resigned his commission on the spot.
He then became the mercenary we met in DF, before discovering his father's legacy in JK.