[1] Miki is known for his distinctively smooth voice and often calm delivery in the roles he has landed.

He often gets cast as handsome young men in anime, perhaps the most notable being Youji Kudou – Balinese (Weiß Kreuz) and Kojirō ("James") (Pokémon).

Other famous roles include Takumi Fujiwara (Initial D anime, video game and mostly Arcade Stage series from Arcade Stage 4 to Arcade Stage 8 Infinity), Kisuke Urahara (Bleach), Akira Yuki (Virtua Fighter), Lockon Stratos (Mobile Suit Gundam 00), Tatsuma Sakamoto (Gintama), Teppei Iwaki (Area no Kishi), Aikurō Mikisugi (Kill la Kill), Hitomi (Code: Breaker), Kagetora Aida (Kuroko's Basketball), Roy Mustang (Fullmetal Alchemist: Brotherhood), Zamasu (Dragon Ball Super), Bob Makihara (Tenjho Tenge), Keisuke Yuuki (Fushigi Yuugi) and Deishū Kaiki (Monogatari Series).

As well as voicing Kojirō, Miki (alongside Mika Kanai, Satomi Kōrogi, Unshō Ishizuka and many other Japanese voice actors) also appears in the Japanese and English versions of Pokémon, where he voiced many of the titular creatures such as Misty's Staryu, Brock's Zubat/Golbat/Crobat and Ash's Charizard.

As he is revealed to have been married, his son, Kazuma begin to follow his father's footstep as a voice actor at age 19 and join a same agency as him in February 3, 2025.