He was voiced by Kerry Shale.
He was the main antagonist of the episode "The Cycle", where Harold was revealed to have been humiliating Richard Watterson all his life, ever since in high school where Harold sent Richard a fake letter by Principal Brown saying that Richard is secretly Prom King. Richard spends one night getting ready for his "Prom King" event, and at the night of the Prom, he takes the crown. However, Principal Brown tells Richard that the letter is fake and has even got "Pwencipal Bron" written on it. Harold chuckles and everyone else laughs at the humiliation. Harold continued to do mean things to Richard until him posing as Richard's therapist was the last straw, and Richard, Gumball, Darwin, and Anais plan to do something mean back to Harold. The four apply a fake $1,000,000 check, Harold finds it and plans to spend non-existent money on things to make him happy. Harold even gets a new wife to replace his first wife, Jackie Wilson. Harold then plans to blow up his house with TNT and replace it with a giant statue of himself. Before Harold can detonate the TNT, Richard whispers to Harold that he'll get a more intensive blast if he stacks the explosives together, which causes him to shake Richard's hand, as they walk away, the Wilsons' house gets blown up. After that, Harold stopped being mean to Richard.
He was a minor antagonist in the episode "The Castle", where he is the first person to arrive at the Wattersons' house after finding out it has no rules. Harold asks Richard if he is allowed as he says he is not allowed to be himself in his family, and Richard agrees. Harold then starts annoying Gumball by poking him saying "I like touching things". More guests arrive and they become Harold's minions. Gumball realizes that they made a mistake, and a rebellion against the Wattersons, lead by Harold himself, starts, leading to Harold kicking the Wattersons out their own house. The Wattersons then disguise themselves as pizza and pizza deliverers. Their plan succeeds and they break in, but they get kicked out again. Nicole arrives and threatens Harold and the others to clean their house and house. Harold unenthusiastically asks what, so Nicole grabs Harold and delivers a stare that terrifies him. Harold, crying like a baby, admits to his comeuppance, and cleans while the others do the same.
Harold can be shown to be a bully in some episodes, (such as "The Choices" and "The Cycle") when he bullied Nathan Daniels into putting money whether he walked in "The Cycle" and bullied Richard Watterson lots of times in "The Cycle" and when criticized Nicole Watterson all her life in "The Choices". But other times he can be shown to be responsible (such as "The Uploads" and "The Points") when Tobias did a naughty prank on him, he grounded Tobias in "The Uploads" and closed Tobias's gaming account for wasting money on imaginary weapons in "The Points". He can also be shown to be annoying to people (such as "The Castle") when he kept on pointing at Gumball in "The Castle".