Has also worked with Yuuichi Nakamura, Marina Inoue, Mamoru Miyano, Hiro Shimono, Kana Hanazawa, Hiroshi Kamiya, Natsuki Hanae, Takahiro Sakurai, Yui Ogura, Daisuke Ono, Yoshimasa Hosoya, Ayumi Fujimura, Maaya Sakamoto, Yu Shimamura, Sora Amamiya, Yoko Hikasa, Ai Kayano, Romi Park, Kaito Ishikawa, Nobuhiko Okamoto, Rina Sato, Jun Fukuyama, Kouki Uchiyama, Junichi Suwabe and Aoi Yuuki in a few roles. Also has admitted that he thinks of Nakamura as a Big Brother Mentor in the latter's show, Tokyo Encounter.
He's also a two-time winner for Best Lead Actor
in the 7th and 8th Annual Seiyuu Award.
He also authored a book that tells his life of how he became a seiyuu called "Itsuka Subete ga Kimi no Chikara ni Naru" and has a manga adaptation of the series.
On June 23, 2019, he announced that he married fellow seiyuu, Ayana Taketatsu.
Roles by Yuuki Kaji:
- Acuo Seiryō in Gamu Kare!
- Acuo Okita in Gamu Kare! Shinsengumi
- Adam Bindewald in Godzilla: Planet of the Monsters
- Adol Christin in Ys: Memories of Celceta, Ys VIII: Lacrimosa of Dana, Ys IX: Monstrum Nox, and Minna Atsumare! Falcom Gakuen (oddly enough)
- Akechi Mitsuhide in Nobunaga Concerto
- Akina Hiizumi in Yozakura Quartet
- Akira in Kimi to Boku
- Akira Nishio in Fafner in the Azure: Dead Aggressor movie Heaven and Earth as well as the 2014 sequel Exodus
- Alibaba in Magi: The Labyrinth of Magic
- Amata Sora in Aquarion Evol
- Anubis Ma'at in Kamigami no Asobi
- Arata Shindo in Psycho-Pass
- Atsuji in Blame! Movie
- Ayato Kirishima in Tokyo Ghoul
- Cygnus Hyoga in Saint Seiya Awakening
- Danny Winters (Jeremy Irvine) in the Japanese dub of Stonewall
- Dick Grayson/Robin (Brenton Thwaites) in the Japanese dub of Titans and Batman Ninja.
- Dug in the Japanese dub of Early Man
- Eight from Dragon Quest VIII (from the Dragon Quest series) in Super Smash Bros. Ultimate
- Eren Jäger/Yeager in Attack on Titan
- Felix Kingsfort in Unbreakable Machine Doll
- Finnian in Black Butler
- Flynn in Shin Megami Tensei IV, also oddly enough. He reprises the role in the sequel/spin-off, but as Flynn's no longer the protagonist, he gets more lines.
- Fromm Vantarhei in Buddy Complex
- Fuyunyan in Yo-Kai Watch
- Gōzanze Myōō/Trailokyavijaya in Namu Amida Butsu! -UTENA-
- Gus Grav in Bakugan
- Hannya and Hoshikumadōji in Onmyōji
- Haru Natsume in Stand My Heroes
- Haruyuki "Haru" Arita in Accel World
- Hatano in Joker Game
- Hearts in 100 Sleeping Princes and the Kingdom of Dreams
- Hilmes aka Silver Mask in The Heroic Legend of Arslan
- Hope Estheim in Final Fantasy XIII and its sequels
- Hyuuga Masamune in Touken Ranbu
- Iemitsu Tokugawa in Akanesasu Sekai de Kimi to Utau, utilizing a deeper voice.
- Issei Hyōdō in High School DxD
- Jowy Atreides in the Radio Drama of Suikoden II
- Judeau in Berserk: The Golden Age Arc, Berserk (2016), and Berserk and the Band of the Hawk. (succeeding Akira Ishida)
- Kakeru Shiwasu in Tsukiuta
- Kakeru Sunahara in Tantei Team KZ Jiken Note
- Kakeru Yuiga in Norn9
- Kanato Sakamaki in Diabolik Lovers
- Katai Tayama in Bungo to Alchemist
- Katsuhira Agata in Kiznaiver
- Kazue Souma in Hakuouki
- Kazuya Ichinose/Akio Fudou in Inazuma Eleven
- Also plays as Kozoumaru Sasuke in Ares no Tenbin
- Kenma Kozume in Haikyuu!!
- Kentucky in Ten Thousand Noble Musketeers
- Koichi Hirose in JoJo's Bizarre Adventure: Diamond is Unbreakable (Anime version, replacing Romi Park, and yes, he raised his pitch to match hers you would have difficulty to think that it was Kaji all along)
- Johnny Joestar in JoJo's Bizarre Adventure: All Star Battle
- Konekomaru Miwa in Blue Exorcist
- Kou Mabuchi in Bkue Spring Ride
- Kouhei Ueno in Mysterious Girlfriend X
- Kouichi Tanemura in Hanasaku Iroha
- Kuro in Servamp
- Leo Luis in Mobile Suit Gundam AGE
- Leonis in Agarest Senki Zero
- Link in Hyrule Warriors
- Liu Bei (Ryuu Bi) Gundam in SD Gundam Sangokuden Brave Battle Warriors, SD Gundam G Generation World, and Super Robot Wars UX
- Lyon Vastia in Fairy Tail
- Mao Isara in Ensemble Stars!
- Maurice Hall (James Wilby) in the Japanese dub of Maurice (second dubbed version)
- Mei Narumiya in Diamond no Ace
- Meliodas in The Seven Deadly Sins
- Megumu Hanemura in Zetsuen no Tempest
- Naturezza in the Captain Tsubasa smartphone game Tatakau Dream Team
- Nishikata in Teasing Master Takagi-san
- Nell Hydra in Blood Lad
- Private Norman "Machine" Ellison (Logan Lerman) in the Japanese dub of Fury
- Norman The Guinea Pig in the Japanese dub of The Secret Life of Pets
- Osamu Mikumo in World Trigger
- Oscar in Lupin III: The Woman Called Fujiko Mine
- Q-Vier in Valvrave the Liberator
- Rawn in Dragalia Lost
- Rentaro Satomi in Black Bullet
- Ritsu in RENCAROID
- Ryuichi Naruhodo (Phoenix Wright) in the anime adaptation of Ace Attorney
- Sabito in Demon Slayer: Kimetsu no Yaiba
- Saburo Nekomiya in Ōkami-san
- Satoru Asahina in From the New World
- Seth in Under Night In-Birth
- Shion in No. 6
- Shiwasu Kakeru in Tsukiuta
- Shizuka Kira in Do-S ni Koishite
- Shoto Todoroki in My Hero Academia
- Shuichirou Hama in Nintama Rantarou
- Shu Ohma in Guilty Crown
- Sieg in Suikoden Tierkreis
- Suō Sōsuke in KLAP!! ~Kind Love And Punish~
- Souta Mochizuki in Confession Executive Committee
- "Speed of Sound" Sonic in One-Punch Man
- Takeo Takumi in Star Driver
- Takeru Homura/Soulburner in Yu-Gi-Oh! VRAINS
- Takeshi Aiza in Your Lie in April
- Takumi in Fire Emblem Fates and Fire Emblem Warriors
- Takumi in Kabaneri of the Iron Fortress
- Thoma Avenir in Magical Girl Lyrical Nanoha A's Portable : The Gears of Destiny
- Tatara Totsuka in K
- Tatsurou Kosugi in Bakuman。
- Terunori Kuga in Food Wars!
- Tōma in Magical Days – The Brats' Parade
- Toyotomi Hideyoshi in Nobunaga the Fool
- Variation in Ixion Saga DT
- Veight in Granblue Fantasy
- Virgil in Pokémon Best Wishes
- Citron (Clemont) in Pokémon X and Y
- Walker Yumasaki in Durarara!!
- Wolfgang Amadeus Mozart ("Motz/Motes") in Classicaloid
- Wataru Asahina in Brothers Conflict
- Yakumo Koizumi in Ayakashi: Romance Reborn
- Yoh Takami in Deadman Wonderland
- Yukine in Noragami
- Yuuya Haibara in Danball Senki and Danball Senki W
- Yomi in Phantasy Star Nova
- Youto Yokodera in Hentai Ouji to Warawanai Neko
- Zen in Persona Q: Shadow of the Labyrinth
