Yazawa started her manga publishing life in 1985. She studied in a fashion school but later dropped out. Throughout her 15 years of publishing, she wrote over 10 series in Ribon. While most of her manga continues to be published in Japan by Shueisha, publishers of Ribon and Cookie (in which Nana is serialized), series like Paradise Kiss now appear in other magazines such as Zipper, published by Shodensha. ???????

In June, 2009, it was revealed that Yazawa had contracted a sudden illness, and had to be sent to hospital for treatment, putting Nana on hiatus. She returned from hospital in April, 2010, although has yet to reveal when or if she will be continuing the Nana manga serialization.

Yazawa's most famous mangas include Tenshi Nanka Ja Nai (I'm Not an Angel), Gokinjo Monogatari (Neighborhood Story), Paradise Kiss, and Nana. All five volumes of Paradise Kiss have been released in English by Tokyopop. Nana was formerly running in Shojo Beat and is now being released by Viz Media, bi-monthly. In Japan it continues to run in Cookie and is currently up to 84 chapters, plus three side story chapters about different characters' early lives. In 2003, she was awarded the Shogakukan Manga Award for Nana. Nana was made into an anime (produced by Madhouse Studios) and a successful movie with a sequel in Japan.

Yazawa's works are most popular among people who love fashion. The storylines generally are centered on young women and their relationships, something with which her young fanbase identifies. The characters are always very stylish, and she is known especially for her hip sense of fashion. Yazawa herself attended a fashion school after high school but did not complete her studies there. Another key point is her strikingly unique, often rebellious characters, who tend to be juxtaposed against the more traditional ones.

She has also published three artbooks.

Yazawa is a fan of Rumi Shishido and routinely promotes her works; in one of the volumes of Gokinjo Monogatari, she promoted Shishido's first indies album, Set Me Free, and likewise designed the cover for her third indies album, Rumi Roll, which was promoted in volume 9 of NANA.