Background
Mylo spent his late teens as a padawan in the Clone Wars. Most of that time was far from the front lines, helping arrange back channels for supplies and communications. This immersed him in the seedier side of the galaxy, and as the war dragged on and got worse he began to become disillusioned with the Jedi, feeling that the order had lost sight of its purpose.
When he got news of the purge, he was away from his party and assumed they were already lost or soon to be. He went to ground immediately, and managed to survive by laying low. While he avoided any overt use of the Force, he continued to meditate in private, fighting off the fear and anger that seemed to permeate the galaxy for decades.
Unable to shake his Jedi dedication to justice, he set about fighting corruption both within and outside the system, using threats, blackmail, and occasionally outright violence to keep both government officials and back-alley criminals in line.
After the "fall" of the Empire, he was too cynical to get caught up in the victory propaganda. The card-carrying Imperial military and bureaucracy numbered in the billions, to say nothing of sympathizers. Never mind that the New Republic is probably just as prone to corruption as the old one, even if it hasn't hit that point yet. No, it'll be a long, bloody fight to really restore peace and justice.
Motivation
Striking a blow against real corruption. Tipping off Sector Rangers to a local slave ring barely registers to the people up the chain, and leaking the planetary governor's real estate racket to the press on a speck-on-the-map mid rim world hardly makes the news outside that system. But bringing down someone big, making a REAL difference....