Himawari is bright, cheerful, and full of energy. She loves to have fun and always has a bright outlook and loves being a VTuber. Before becoming a VTuber however, she seemed to have serious self-esteem issues and trouble at school, leading to her missing a semester. Himawari admitted that becoming a VTuber turned her life around and that meeting everyone in NIJISANJI was one of the best things that ever happened to her and encourages people not to give up.
Himawari is part of the group known as the Dokuzuhonsha (どくずほんしゃ) with Kuzuha, Dola, and Yashiro Kizuku, which they role-playing as a family during collab streams with her being the elder sister. However, even outside the Dokuzuhonsha collab streams, Himawari is very close to Dola, often staying at her house and doing streams of just the two of them talking or playing games. Dola even lent her some of her pajamas when Himawari stayed overnight. She's also very close to Yashiro as well, who she refers to as 'Papa' and who helps her study.
Honma Himawari is famously air-headed and 'lacking in certain academic fields' (to put it kindly). In her earlier streams she would point at the screen, forgetting her audience couldn't actually see her, answered the door in nothing but a towel once, and thought the sun and the moon were the same thing (something that one of the COO's of the company that manages the NIJISANJI project, Iwanaga, commented on).