Atsuo Hasegawa is a Japanese voice actor born on January 4th in Saitama Prefecture, Japan. He is affiliated with the talent agency Office PAC. He stands approximately 184 cm tall and has a proficiency in handball.

Hasegawa's career in animation began in the mid-2010s, with his earliest listed roles appearing in 2014. He has since built a portfolio of supporting and guest characters across a variety of television anime series, original net animations (ONA), and animated films.

His television credits include roles in several popular and long-running franchises. He has appeared in multiple installments of the Lupin III series, with roles such as a male customer in Lupin III PART4, a terrorist in Lupin III PART5, and Derrick Barnes in Lupin III PART6. He has also voiced characters in the Fairy Tail series, including a hammer man in 2014 and a department manager in 2015. In the anime adaptation of Akashic Records of Bastard Magical Instructor, he played the role of Zelos Draghart. He also contributed voices to the fantasy series Rage of Bahamut: Virgin Soul and the historical drama Altair: A Record of Battles.

One of his more prominent roles is in the popular sports anime Yuri!!! on ICE, where he voiced the French skater Alain Leroy. His work also extends to the Garo franchise, with appearances in Garo: The Animation, Garo: Crimson Moon, and Garo: Vanishing Line. In addition to television, Hasegawa has voice acting credits in animated films. He had a role in the 2018 movie Milky Panic twelve, where he played a character named Chickento. He also appeared in the film Lu over the wall and various Lupin III theatrical features.

In the realm of original net animation and video games, Hasegawa has voiced a Zeon soldier in Mobile Suit Gundam Thunderbolt and a gatekeeper in the 2019 adaptation of Blade of the Immortal. His video game credits include roles in Tactics Ogre: Reborn, Final Fantasy VII Rebirth, and the Japanese versions of Ace Attorney 5 and Romance of the Three Kingdoms XIII.