There is no official record of Luka in any Republic database until he showed up on list of ships passengers nearly a decade ago. He has kept to the space lanes since then working aboard various vessel as trader, smuggler, and eventually pilot.
He arrived on the Smuggler's Moon and somehow acquired a ship through questionable means. At first he started as an explorer, but then perhaps from the influence of Nar Shaddar dipped his toes into smuggling. A dip of the toe turned into a full plunge and he through himself in the work for the challenge of it. As a smuggler he was ridiculously successful, but not without making enemies.
When Lord Eebua the Hutt took over the smuggling ring that Luka was a member of he refused to work for the Hutt and decided to remain independent. When Eebua took over more and more of Nar Shaddar and started threatening Luka's bottom line he took offense to it and arranged to fight back in hopes of giving the Hutt Lord a black eye and jump starting the small resistance to the Hutt Lord operating on the Moon. The fight back took the form of the massacre of Lord Eebua's Starport on Nar Shaddar. Hundreds of civilizations were killed, dozens of trade ships destroyed or damaged, but three fully crewed, expensive Dreadnought ships were taken down in the process.
Labeled a terrorist for his actions Luka was eventually captured and disappeared from view with Eebua promising a public execution for his crimes... but that spectacle never came. Rumor had it that he was being held in Shadowgate Prison and used as entertainment for the Hutt Lord's whenever he wanted to see him tortured. Now that Eebua was dead, Luka has been spotted again roaming free on the Moon, his debt to society apparently paid?
Not everyone seemed to agree that his debt was paid. he was last seen beaten unconscious and being carried away into an unmarked airspeeder on the Smuggler's Moon.