Masashi Igarashi is a Japanese actor and voice actor born on November 4, 1983, in Shizuoka Prefecture. He is affiliated with the talent agency ACROSS ENTERTAINMENT. Before pursuing a career in entertainment, Igarashi worked at a factory after graduating from high school. Inspired by a televised musical featuring idols, he decided to change his path and enrolled at Waseda University, from which he graduated. He began his entertainment career in 2009 as an actor, appearing in stage productions, films, and television dramas. He transitioned to voice acting in 2016.

Igarashi is best known for his role as Minato Takahashi in the King of Prism series. He first voiced the character in the 2016 theatrical film King of Prism by PrettyRhythm. He has since reprised the role in multiple installments of the franchise, including the 2019 television anime King of Prism: Shiny Seven Stars, the film King of Prism All Stars: Prism Show Best 10, and the 2025 film King of Prism -Your Endless Call- Miinna Kirameki! Prism☆Tours. He has also portrayed the character in stage adaptations, such as King of Prism -Over the Sunshine- in 2017.

Another significant role for Igarashi is Citron in the A3! franchise. He voices the character in the A3! smartphone game, which began in 2017, and in the 2020 television anime adaptations A3! Season Spring & Summer and A3! Season Autumn & Winter. Citron is a cheerful and eccentric foreign exchange student who serves as the mood maker of the Spring Troupe.

In addition to his anime roles, Igarashi has lent his voice to characters in video games. He played Jack Rose in Cocktail Prince and Yoren Baekrin in Scales of Precatus. His work also extends to music, as he has performed character songs for both the King of Prism and A3! franchises. He announced his marriage to a non-celebrity woman in October 2020.