In 1985, she married Shigeru Nishikawa, the vocalist of the rock heavy metal band PRESENCE and gave birth to her eldest son in 1989.

Tada made her debut in 1977, when still a high-school student, on Shueisha's "Deluxe Margaret" magazine. Tada's stories belong to the shoujo genre of manga and feature love stories centered around young female characters and their love interests. The storylines include comedic moments and are characterised by essential and sharp drawings. Some of Tada's most popular works are Aishite Knight, Itazura na Kiss and Kimi no Na wa Deborah.

Aishite Knight portrays the Japanese rock music scene of the early 1980's. The anime series based on Ai Shite Knight was the first ever to feature original songs performed within the episodes. Another of Tada's works, Miha Paradise is also set in the rock 'n' roll world.

Itazura na Kiss (Mischievous Kiss) - begun in 1991 and never completed - was by far Tada's most successful work in Japan.
It tells the love story between Kotoko and Naoki from high school until after their marriage. The series inspired also an illustrated art book "Itazura na Kiss Illustration Shuu" and two novels written by Nori Harata and published in Shueisha's "Cobalt" series. In 1996 a live action Japanese TV series based on Itazura na Kiss was also produced, starring Aiko Satoo as Kotoko and Takashi Kashiwabara as Naoki. In 2005, the series was adapted into a Taiwanese drama under the name of It Started With a Kiss.

Kaoru Tada died on 11 March, 1999, aged only 38, following a domestic accident which occurred while she was moving to a new house with her husband and son.