Harold is Billy's father. Harold is where Billy gets most of his traits from, most noticeably his giant pink nose and idiocy. He apparently has no job, because in one episode he is a doctor, while in others, he is said to have worked at Freckle Burger but got fired for eating all the paper cups so his employment is currently unknown, though it was mentioned that he was once a Navy SEAL and possesses traits that could back up this claim (can fish in a general sense and possesses an understanding of dangerous or traumatic situations with a calm, commanding ease). He was also in a rock band once, and changed his name to "Mogar". He is one of the people featured in the slideshow of who stole Grim's scythe in. Like Billy, Harold is very stupid and is prone to do stupid things. He sees Billy as a genius due to the boys' "genius" when Billy was young and tries to get others to see this too. Despite this, he still gets annoyed sometimes by Billy's antics. He is afraid of Santa Claus and his wife, Gladys, who is mentally unbalanced. Harold is a voracious eater, and willing to eat anything. He once said that he was still so hungry after eating two breakfasts that he couldn't wait til lunch and so knowingly ate his wifes mucus covered pet rat live. While Harold is an idiot, he is still noticeably smarter than Billy. The Harvard acceptance letter makes it entirely possible that Harold is academically a genius, but lacks any sensibilities, whereas his son lacks both of these. He passed along the ability to dance ballet excellently to his son, showing they might both be idiot savants. His pompadour actually contains his brain, and in earliest episodes he had appeared more intellectual, but as the series went on he appeared to get dumber.

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