Complex sentence: Briefly going legitimate, Humphreys got a job as a short-order cook at a restaurant on Halsted Street, though Murray's "legitimacy" would be short-lived after he made the acquaintance of customer Fred Evans.
Split into simpler sentences: Briefly going legitimate, Humphreys got a job as a short-order cook at a restaurant on Halsted Street. But Murray's "legitimacy" was short-lived after he made the acquaintance of customer Fred Evans.