Gevanni is a tall, attractive man with black hair and bangs that hang just over his light blue eyes. He is always seen wearing a black suit and often keeps a gun on his person for security measures.
Gevanni is very talented, having skills which include lock-picking, investigating, monitoring and following suspects, and the ability to forge writing. Even after numerous deaths in the SPK, Gevanni remains a loyal member; this is indicative of his trust in Near. Moreover, he has a key role in Near's plans and becomes essential to solving the Kira case by following Teru Mikami and subsequently forging a Death Note. Series creator Tsugumi Ohba described Gevanni as a "good-looking hotshot" who received an invitation to join Near's team because of his ridiculously amazing skills. According to Death Note 13: How to Read, "the Kira case couldn't have been solved without him." The book also states that Gevanni likes "ships in bottles" and dislikes "unreasonable superiors."
In most of his early scenes, Gevanni comes across as being in charge of the SPK's computers and communications, such as when he puts Near through to "L" (Light Yagami) during one of their online confrontations, or re-establishing communications when the SPK moves to a new HQ. He also drives Aizawa to and from the SPK's HQ for a meeting with Near. Gevanni starts to play a more important role when the team moves to Japan. When Near suspects Mikami of being the new Kira, Gevanni is assigned to shadowing the young prosecutor almost full-time. His meticulous analysis of Mikami's personal habits plays a role in both Light's and Near's plan, but will ultimately allow Near to realize Light's true intentions and, as such, allows Gevanni to swap the real Death Note with a fake, forged in record time by Gevanni himself. In the one-shot chapter set three years after Light's death, while he doesn't have any speaking lines or real involvement, Gevanni can be seen with Anthony Rester and Halle Lidner during Near's broadcast to the world as the new L.
- In some online manga scanlations, his last name is sometimes misspelled as the common name "Giovanni."