Locke is cheerful, adventurous, and courageous. He is always eager to go exploring and look for treasure, and is particularly eager to fight the Empire. He is often snarky and sly, making jokes at the expense of others (particularly Edgar) and coming up with bold plans. A running gag in Final Fantasy VI is that Locke loathes being called a thief and insists he is a "treasure hunter".

Despite his outward pleasant demeanor, Locke is motivated to fight the Empire out of guilt; his lover Rachel was killed in an Imperial raid and Locke blames the Empire for her death, but he also blames himself, as Rachel had developed amnesia saving him from a fall and he had left her to start a new life without him when the raid occurred. Locke has spent an untold amount of time scouring the world for a rumored "treasure" the Empire has that can revive the dead, to use it to revive Rachel and atone what he feels is one of the worst mistakes he has made.