Knuckles seems like a rather chill individual, although he can be grumpy at times and is easy to anger, and is a tad bit shy around girls. (tsundere?) 
Treasure hunting is his main love and passion, aside from his badass hat, of course. During his journeys and treasure adventures, Knuckles has gained much knowledge and is aware of many things of Planet Freedom, and has good fighting and gliding skills, as well as tech knowledge. He dislikes being bossed around.

And for some reason he's Texan.