Sei Ashina, whose birth name was Igarashi Aya, embarked on a remarkable journey, transforming her stage name to reflect her artistic aspirations, a testament to her growth and evolution as a performer. Prior to her foray into the world of acting, Ashina initially established herself as a model, gracing the covers of prominent and influential magazines, including Shogakukan's CanCam, a well-known and respected publication in the Japanese entertainment industry, as well as Shueisha's Pinky, a popular and widely read magazine that showcases the latest fashion trends and styles.
In 2002, Ashina made her television debut in the TBS series, "The Tail of Happiness" (しあわせのシッポ),a significant milestone in her career, marking the beginning of her journey as a professional actress.