Starting his career first as a mangaka's assistant (self-described as "horrible" and "lazy" in said assistant position), and later an H manga artist, he went on to enjoy somewhat limited success with other relatively unknown manga titles such as Angel Dust, Coyote, Gun Mania and Hi-Tension. His first major success came with his manga series Hellsing, which got its start and was subsequently serialized in a monthly manga magazine, Young King OURs, towards the latter half of 1997.
However, Hellsing was not the earliest Hirano series to be published in Young King OURs monthly. In 1996, the very same year Hellsing's precursor, The Legends of Vampire Hunter, was first released as a single H short story in Heavenly Pleasure (a monthly H-centric manga magazine), another WWII-based short story named Hi-And-Low was being published in Young King OURs by a then lesser-known Kouta Hirano. The story takes place primarily at a train station in Russia and features two female characters that are strikingly similar to Integra Helsing from Hellsing and Yumiko/Yumie in Crossfire; and who are, in actuality, undercover Axis spies in-league with one another for a common purpose: the success of Operation Barbarossa. This story saw ink in one issue of OURs before being discontinued in favor of Hellsing itself.
A decent number of Hirano's older works are now considered collector's items due to the small number of them that exist. Many characters from Hellsing appear in his previous works and, as mentioned above, there is a rare hentai prototype of Hellsing titled The Legends of (the) Vampire Hunter. At Otakon 2006, he said in an interview that in about a year and a half to two years, he will finish Hellsing and move on to a different project which he says will be kept a secret until the time comes. This statement was proven true when Hellsing ended with 95 chapters in October 2008. Hirano has since begun a new series, Drifters, which will be published in April 30's issue of YKO.
Alphabetical list of works
Anderson, a mafia assassin, tries to escape from the police after being betrayed and backstabbed by the organization he works with (taking along with him 50 kilograms of heroin). To trick his pursuers, he dresses up as a priest and hides himself in a village. A nun named Kris, offers him work at the church and he accepts, seeing this as an opportunity to live the rest of his life atoning for his sins.
But one day Flanders, a mafia member (and an ex-partner of Anderson) finds the church he works at and, while Anderson is absent, he and his partners repeatedly rape Kris. They demand the return of the stolen heroin and threaten to kill Kris. But Anderson proves too skilled for them to handle and he defeats them. Kris and Anderson now flee from the organization and its leader, the ghost of a Nazi.
- Hirano says that he enjoys Eiichiro Oda's series, One Piece. At the end of Hellsing volume 5, he states that he would like to feel up Nami, for instance.
- In a panel question at Anime Expo 2005, Hirano stated his favorites: his favourite male characters were Alucard and Alexander Anderson, and his favorite female character was Seras Victoria. But in the current Sakura-Con, a fan asked him to illustrate his favorite character and he sketched The Captain; then at Animagic 2007, when asked about his favorites, he replied they were Alucard, Seras and Integra Hellsing, and from Millennium, the Major. Previously, in Otakon, he had said Jan and Luke Valentine were his favorite characters. Probably his tastes are seasonal, according to what he is writing.
- Hirano contributed a piece of fan art to "Project G", a dōjinshi tribute to the manga; Genshiken. The piece features the character Madarame resting and looking at his cell phone.
- Hirano has also been part of a doujinshi circle titled GUY-YA, consisting of himself and Read or Die mangaka Shutaro Yamada.
- The character Kohta Hirano from the manga series Highschool of the Dead is based on him.