His nearly 100 films include "Hara-Kiri: Death of a Samurai", which premiered in competition at Cannes in 2011, and "Straw Shield", which was nominated for the Palme d'Or at the celebrated French film festival in 2013.
The Rome film festival said Miike had "reconsidered the boundaries that divide 'populist' practices, genre and auteur visions in some of the most beloved and controversial films in recent years," adding that the Japanese was "considered by Quentin Tarantino to be 'one of the greatest living directors'."
Miike's 2001 Manga-inspired film "Ichi the Killer" in particular sparked controversy for its depiction of bloodlust and violence against women, with organisers at the Toronto film festival famously providing sick bags for the audience when the movie was screened.
Miike has also made films for children, from "Zebraman" to "The Great Yokai War", as well as teen dramas and period pieces.
Artistic director Marco Muller, former head of the Venice film festival, said the 54-year-old had been chosen for the award "for the recurring power of his creative imagination and the courage of his ideas."
"Every one of his films is a breakneck race through a uncannily poetic and surprisingly political imagination. Miike has tried his hand at every genre: when he has chosen to shatter them it has always been to recompose them better in unpredictable mixes," he said.
"Always catching us unprepared... Miike is arguably the least compliant of all the contemporary maverick directors," he added.