Nobuaki Sekine was a Japanese voice actor and actor from Tokyo, born on January 1, 1934. He began his career with the Tokyo Radio Drama Company before transitioning to voice acting. Sekine was affiliated with the talent agency 81 Produce later in his career. He passed away on November 20, 2021, at the age of 87.

Sekine's career as a voice actor was extensive, with credits spanning from the early 1960s to the late 2000s. One of his earliest and most notable film roles was providing the voice of Sanzo-hoshi, also known as Tang Sanzang, in the classic 1960 anime film Alakazam the Great. In the 1965 television series Kimba the White Lion, he voiced the character Kenichi.

His television anime credits are numerous and include a wide variety of supporting and guest roles. He voiced Mauro in the 2002 sci-fi series Heat Guy J. Sekine also played the recurring role of Gaohai (referred to as Gao Hai or Kao Hai in some sources) in the popular series Code Geass: Lelouch of the Rebellion R2. He appeared in the long-running series Gintama as an unnamed Superior and had multiple roles in the long-running franchise Nintama Rantarō. Sekine contributed to several acclaimed mystery series, with appearances in both Case Closed (as Katsuhiko Nakamoto and Shitara Jukichi) and The File of Young Kindaichi (as Koshiro Nagasaki). Other notable credits include roles in.hack//Legend of the Twilight, Avenger, Noein, and Master Keaton. He also voiced the character Yamanoue no Okura in the OVA series Anime Koten Bungaku Kan and Go Inkyo in the web anime Ikuze! Gen-san.

In addition to his voice work in animation, Sekine was a prolific narrator. He was particularly well-known for providing the story narration for NHK's morning serial drama television novels (asadora) from 1990 to 2001. His work also extended to live-action puppet dramas for NHK, such as Shin Hakkenden and Sanada Juuyuushi, and he provided voices for educational programs. His career demonstrated a long-standing commitment to both character acting and narration across a variety of media in the Japanese entertainment industry.