Miki Jonouichi serves as the chief mechanic for the Sugo team in the world of Cyber Formula racing. She has short red hair and brown eyes, and her personality is often described as tomboyish, with a strong preference for rock music. Her role primarily involves the maintenance, repair, and optimization of the team's race cars, most notably the Asurada series. She possesses a high level of technical skill, being one of the few mechanics capable of fully interfacing with Asurada's complex artificial intelligence system, and she is adept at data analysis, often predicting mechanical failures before they occur on the track. Miki is known for her dedication and ability to work under intense pressure, sometimes putting in long shifts to repair damaged vehicles.

Her relationship with driver Naoki Shinjyo is a significant aspect of her character arc. She was initially impressed by his fighting spirit when he was an F-3 racer, and she later becomes his love interest. This connection eventually leads her to accompany him to the American racing scene during the later OVAs, marking a major subplot in her development. She also had an early skepticism about Hayato Kazami's abilities when he first became Asurada's driver, but she grows to respect him as part of the team. Throughout the series, Miki's motivations are rooted in her technical passion and her desire to support the drivers and the team, often clashing with those who treat race cars merely as tools rather than partners. Her character shows steady growth from a competent but somewhat impulsive mechanic into a more seasoned and loyal crew member who plays a vital role in the team's success.