Professor Hinkle, despite his name, is not really a professor. He's a magician... and the crappiest one at that. He is voiced by Billy De Wolfe.
Professor Hinkle is an ineffectual villain who joined up with Luciuas and his group for a chance at the big time several times, but failing each time
Eventually the team fell in despair and accepted a call from Slade which would help them recover. However he turn-coated and aided Chuckles when they joined Joker in his plans to destroy it. Afterwards Hinkle was left in despair until Chuckles' new boss, Marceline's dad, approached him with another opportunity for takeover. He took it and helped the villain and his goals. He was shot down by Darkwarrior just like Chuckles in their last showdown, though.