In the anime, Rei Hino was a hot-headed, strong-willed, and somewhat bossy yet well-meaning girl who wanted to be everything from a globe-trotting business woman to musical idol, as well as have a boyfriend (Rei in the Sailor Moon musicals was portrayed this way as well). Sailor Mars did have another side in the anime; her loyalty to Sailor Moon was extremely strong, and her determination and sense of justice were admirable. She seemed to show her affection to the people she cares the most about in odd ways, such as her teasing Usagi or joking with Yuuichirou. Though Rei sometimes bickered with Usagi, she clearly cared about her and valued her friendship very much, and often seemed closer to her than the other Senshi. (In the Stars season, she was the first person whom Usagi told that Mamoru had not contacted her, and Rei was so distraught that she wondered out loud why Usagi had to suffer so much.)
In the manga, Rei Hino was a stoic, serious individual who did not involve herself with men (due in part to her estrangement from her politician father). She displayed what could be described as the Japanese ideal for women: she was reserved, beautiful, and intelligent. Rei's manga image was more fitting with her role as a miko than her anime personality. She and Minako had a strong bond, similar to that seen in the live-action series.