Sakamoto is the Minazuki family's butler and takes care of Karen when her parents are overseas as famous musicians. He is very respectful to her and refers to her ojou-sama, but he also seems to be fond of her, like a father. He worries about Karen being lonely because of her parents are away, and is very happy she made friends during the series. As a butler, he drives to Karen to school, often accompany her and knows how to cook. He also knows how to drive a boat.
(Source: Pretty Cure Wiki, edited)