Haruyoshi Miura is a math teacher in a university. He often helps his daughter with her math and, according to her, usually treats her like a baby.
When Tsunayoshi Sawada was working on a math problem that he and the others couldn't solve, Haru Miura called her father to help them with the problem. To try and prove that Reborn was the infant genius mathematician, Dr. Borin, he purposely gives the wrong answer to the math problem. Reborn then gives the correct answer, leading him to the conclusion that Reborn is Dr. Borin. Later on, he asked Haru to go the eyewear store to pick up his glasses because he was extremely near sighted. Haru then used these glasses to help I-Pin see better.
In the future, he and his family had moved out because of the danger they faced while the Millefiore Famiglia was eliminating every single person associated with the Vongola Famiglia. Before they left, they wrote a letter for Haru and left it in her room.
- He was a surprise guest at one of Haru's Haru Haru Interview: Dangerous, invited by Reborn. And is often mentioned by Haru in the introduction of her interviews in the manga volumes.