Kansuke Yamato is a police inspector from the Nagano Prefecture in Detective Conan. He is 35 years old and holds the rank of inspector within the Nagano Prefectural Police. His most distinguishing features are the physical scars from a near-fatal incident in his past; he lost his left eye to a snow avalanche, which now bears an X-shaped scar, and the same event caused severe and permanent damage to his left leg, forcing him to use a forearm crutch for mobility.

Yamato grew up in a small village in Nagano alongside his future subordinate, Yui Uehara. As children, both were deeply inspired by a local police officer and town hero named Kuroto Kai, an admiration that motivated them to join the police force. The tragedy that led to his disabilities occurred one year before the Furinkazan Case. Yamato was pursuing a parole jumper whom he suspected was involved in the mysterious death of Kuroto Kai. The pursuit led him into a mountain where he was caught in an avalanche. He was missing and presumed dead for several days. His childhood friend, Taka'aki Morofushi, who is also a police inspector, disobeyed orders to search for him, eventually finding the criminal and rescuing Yamato. After a lengthy recovery, Yamato returned to police work and continued his investigation into Kai's death, a case that was eventually solved with the help of Conan Edogawa and Heiji Hattori.

In personality, Yamato stands in stark contrast to other recurring police inspectors. He is depicted as exceptionally serious and hard-boiled, often short-tempered and known to intimidate suspects with his intense demeanor. He becomes visibly annoyed by the ignorance displayed by Kogoro Mouri or the goofiness of Inspector Misao Yamamura. Despite this rough exterior, he possesses a softer side that he rarely shows. There are hints that he is aware of and accepts Uehara's romantic affection for him, though he typically responds to her overtures with gruff scolding.

Yamato's role in the story is primarily as a capable regional authority figure who frequently collaborates with the main cast on complex cases within the Nagano region. His key relationships are central to his character. His bond with Yui Uehara is deep and complex; she is his direct subordinate and childhood friend who affectionately calls him Kan-chan, a nickname he always scolds her for using. He was upset by her departure from the force but readily accepted her back as his partner. His friendship with Taka'aki Morofushi is marked by a petty rivalry, with the two often competing to solve cases first. This rivalry belies a profound loyalty, as each has proven willing to risk their life for the other, such as when Yamato ran into a burning building to save Morofushi.

In terms of development, Yamato has evolved from a driven detective haunted by the unsolved death of his hero to a more settled inspector who has found closure on that chapter of his past. His journey also includes the personal reconciliation with Uehara, allowing her back into his professional and personal life. Regarding notable abilities, despite his physical disabilities, he is a highly active and formidable investigator. His physical resilience and investigative acumen are highly respected. Furthermore, he is one of the few characters in the series who recognizes Conan Edogawa's extraordinary intelligence, often treating the boy as an equal and an adult rather than dismissing him, and he has been shown to suspect that Conan is the true mind behind Kogoro Mouri's famous deductions.