John Allen Hill (played by Keene Curtis) is the owner of Melville's, the seafood restaurant located directly above Cheers. Though Melville's was mentioned often throughout the series, Hill did not first appear until season 9, during which he bought the restaurant and first became its proprietor.
Upon first meeting Sam he informed him that the deed for Melville's included the space Cheers was using for their bathrooms and pool room (they had been Melville's former storage area). He demanded Sam start paying rent for the area. Sam initially refused resulting in Hill building a brick wall sealing off the back rooms. Sam eventually capitulated and continued to pay monthly rent to Hill until he and Rebecca became business partners, purchasing the back rooms from HIll for $30,000.
Hill is a pompous, acerbic, older man with a disdain for the Cheers gang, he considers them to be low-class buffoons. In the season nine episode entitled Achilles Hill, Sam dated Hill's daughter Valerie as a way to get back at Hill for his condescending attitude towards the himself and Cheers.
Hill and Carla have a complicated love-hate relationship; they frequently insult and curse each other even during their frequent periods of sexual liaison.