Morikubo graduated from
Third Junior & Senior High School of Nihon University in 1992, and dropped out of
Tama Art University. Before becoming a full-fledged voice actor, he worked at a talent agency, and was recruited by people in the voice acting industry who saw a performance by the Onigiri Skippers, a theater troupe he founded with his seniors from the lab party he attended in elementary school. During his first dubbing session, he made sounds out of flipping pages on the script because he had no experience as a voice actor at that time. The script for the first episode had four pages of long dialogues from the first page, and the sound director said that he would never have let him do the role if he had known he would talk so much. He made his voice acting debut in 1996 as a Mini 4 Fighter in ''
Bakusō Kyōdai Let's & Go!!''. The show was supposed to finish in a year, but due to its unexpected popularity, it became a long-running production, and he moved from the agency where he had worked as an actor to a voice acting agency. Since then, he has been active in a variety of fields including animation, games, radio personality, music, and stage. After working at
Sigma Seven, Morikubo moved to VIMS, an office affiliated with
Arts Vision. In 1998, he and voice actor
Hideo Ishikawa started a music unit called "
Anzu" (derived from the only fruit Morikubo could eat), and in 1999, they formed the band "AN's ALL STARS" with other band members. In August of the same year, he formed the band "Mosquito Milk". In 2001, Morikubo made his solo debut under the Capcom
Suleputer label, and in 2008, he debuted again under the Lantis label. In 2010, he formed "Buzzy→Bee" as a solo project, and in January 2015, he became the second DJ of the long-running bayfm program "KEIYOGINKO POWER COUNTDOWN JAPAN HOT 30". In 2016, he received the
Kei Tomiyama Memorial Award at the
10th Seiyu Awards. In 2020, he received the Personality Award at the
14th Seiyu Awards. On August 31, 2018, Morikubo left VIMS. On September 1 of the same year, he established Add9th and assumed the position of its representative director. Morikubo married fellow voice actress
Yū Asakawa on February 22, 2007. On January 14, 2009, Asakawa announced on her blog that the two had amicably divorced, citing differences in personality as the reason for the separation. On July 4, 2014, Morikubo announced on his blog that he had gotten married that week, but expressed a desire to keep details of the marriage private, including the identity of his wife due to her being uninvolved in the entertainment industry. On December 28, 2017, he revealed on an episode of his radio show The BAY☆LINE that he and his wife had welcomed a daughter earlier in the year. The same day, he reaffirmed the news via Twitter. He and
Kentarō Itō call each other their best friend. Morikubo has been in charge of the stage music for the K-Show theater company, which Itō presides over, since its inception. In August 2024, Morikubo, among others including
Hiroshi Tsuchida, participated in a stage reading based on 's manga , themed after the
persecution of Uyghurs in China. This fuelled fan speculation of Morikubo being removed from his roles of the characters Ifa in
miHoYo's
Genshin Impact on March 12, 2025 and Elysium in
Arknights three days later on March 15, 2025, both of which were developed in mainland China, out of political reasons stemming from his involvement in the live reading. ==Filmography==