Duff's CEO, also known as Duff's President, is the head of the Duff Beer company. He has been the CEO of Duff since 1997. He presumably lives in Capital City near the Duff Brewery. He spoke with a very thick Texan accent.
When alcohol is banned in Springfield, he starts releasing Duff Zero, which is non-alcoholic. He claims people like Duff for its taste, not the alcohol. He is wrong and Duff goes out of business shortly afterwards, with him casually stating "well, that's the end of me", though it's likely they recovered after the alcohol ban was found to have been repealed, as Duff is still sold in later episodes.