Satoru Kumatsuka is a freelance photographer and is the father of Kirin and husband to Yayoi Kumatsuka, a drama teacher at Morinomiya Academy.
Satoru is a tall slim man with short and light, orange-red colored hair and slanted eyes with dark irises, a trait his daughter Kirin inherits. His face takes on a flushed appearance whenever he dotes on Kirin or is around his wife Yayoi. He normally dresses in suits.
Satoru is a very flirtatious man, often commenting and complimenting on a woman's appearance. However, Satoru is also a big family man and very affectionate towards his wife Yayoi and daughter Kirin. He is very protective of his daughter, absolutely forbidding Kirin from kissing or getting close to any of the boys at the daycare, calling them "filthy little beasts". However, he appears to gradually accept the Kashima brothers as the more acceptable males.
Satoru also becomes extremely jealous whenever Yayoi speaks to someone of the opposite sex. He is a very bubbly person whenever his daughter is around and is always seen with a camera in hand to snap a shot, however he becomes easily discouraged whenever his daughter says that she hates him or that she prefers Yayoi over him and is seen visibly distraught.
Satoru first met his wife Yayoi when she was playing the lead role in a play while attending Morinomiya University. At that time, Satoru was pursuing a career in photography and described himself as being in a very "agitated" state of mind during that time which caused Satoru to be very cruel to Yayoi when he went backstage to look for a photography entry model. Though he thought the play was boring and Yayoi's acting was a nuisance, for the next three days that the cast were performing on every one of those days, Satoru was in attendance. When he finally clapped for her at the end of her performance, Yayoi was so overcome with happiness that she began to smile, shocking Satoru and making him bashful in her presence. For Satoru, he claimed that it was "love at first sight" and ever since then he is always bashful when Yayoi makes the first move. Shortly after, Satoru married Yayoi and had their daughter Kirin.