Kudo began her career age just 14 in three-piece pop unit Seventeen Club, formed from a 1984 'Miss Seventeen Contest' organized by Japanese magazine Seventeen. They released two singles in 1985 on Sony Records and Kudo later said she joined "just to have fun."
Onyanko Club debuted on the first of April 1985 on their own Fuji TV variety show Yūyake Nyan Nyan with eleven high school girls selected from participants in the Fuji TV All Night High School Girl Special (オールナイトフジ女子高生スペシャル?) aired in February that same year. Kudo auditioned for the group after completing high school in May 1986, becoming member no.38.
The group gave a new approach to the idol formula with 52 official members and three unofficial members, with several, including Shizuka Kudo, forming sub-groups, such as Ushirogami Hikaretai. Ushirogami Hikaretai, which teamed Kudo with Akiko Ikuina and Makiko Saito released five singles and two albums in a one year period from May 1987 until March 1988 with a live album their final release in July 1988 (Hora ne, Haru ga Kita - First Concert).
Kudo has said of her time in Onyanko Club that "it was a great experience, with good, bad and really dirty things," and that she tried not to learn from the behavior of others around her.
Onyanko Club disbanded on 9 September 1987 with a final concert but Kudo had already launched her solo career with her first single, Kindan no Telepathy less than two weeks prior, on 31 August. It climbed to the top of the music chart and also became a favorite throughout Asia during the early '90s. She enjoyed a run of eight consecutive number 1 singles in Japan between 1988 and 1990, and eleven in total.
She continued to release new music every year until 2000 with sporadic releases since then. Her most recent release came in 2008 when she teamed up with Miyuki Nakajima, co-composer of five of Kudo's late-80s hits, for a double a-side, Night Wing/ Yuki Gasa. Kudo said of their long-term working relationship, "We are not that close. We have a nice distance. Sometimes when I hear her music, it scares me but I especially like her passionate lyrics."
Kudo also appears on television in jidaigeki roles and also creates her own jewelry that is sold in Japan.