Shiga had a starring role as one of the children answering questions in the NHK quiz show Donna Mondai Q TV from 1984 to 1985. She performed the song Yume no Naka no Rondo, which was used as the theme song for the July 1985 OVA Magical Princess Minky Momo: La Ronde in My Dream. In 1986, Shiga played the role of Yumi Hanazono, the main character in Magical Idol Pastel Yumi. Her single, Freesia no Shōnen, was used as a theme song for the same series, and this helped her gain in popularity. After playing the role of Yumi and performing the theme song for the series, she officially made her debut as an idol singer under Warner Pioneer.