She earned the title of "Japan's Original Adult Video Queen" during a 16-year career in which she starred in nearly 200 AVs and appeared in over 180 films.

[4][5] Her death on June 28, 2005, one day after her 35th birthday, ended one of the longest careers in the AV field[2][6] and made front-page news in Tokyo.

In his entry in the Molester's Train series, Molester's Train: Dirty Behavior aka Birthday Hayashi had a role in a film whose "austere tone" was in direct contrast to the light, comic tone of the previous films in the series, started by Academy Award-winner Yōjirō Takita in 1982.

[3] In the role of the "gluttonous woman" who eats herself in Satō's Naked Blood (1996) Hayashi performed what Allmovie calls "one of the most appalling scenes in Japanese horror", in which her character cooks, then consumes various parts of her body.

[21][22] By mid-1996, another V&R Planning director, Katsuyuki Hirano (who was married) had replaced Company Matsuo as Hayashi's lover[18] and the two of them traveled to the north of Japan in July 1996 on a bike trip.

[28][29] In their review of the film, midnighteye.com commented, "The big surprise is that former porn star Yumika Hayashi is also very good as the happy-go-lucky Sachiko".

[30] As one of the top erotic actresses of her day, Hayashi was invited to the Cinequint theater in Shibuya to speak at a woman's-only night showing of pink films in March 2002.

When they realized she wasn't breathing, they quickly called for an ambulance, but it was already too late, Yumika's mom was shattered, screaming, crying and going half crazy.

"[2] A neighbor agreed telling reporters, "About three months ago, she had a huge fight with a guy that forced the cops to be called to our apartment block.

"[2] Hayashi's friend and director Yumi Yoshiyuki disagreed with the possibility of suicide, telling Friday weekly, "She was a really bright kid.

[33] Hayashi's last film, Miss Peach: Peachy Sweetness Huge Breasts (ミスピーチ　巨乳は桃の甘み, Misu Piichi: kyonyū wa momo no umami) (2005), directed by Yumi Yoshiyuki, was released in September 2005.

[34] Yoshiyuki and co-star Sakurako Kaoru participated in the memorial ceremony for Hayashi at the film's opening at the Ueno Okura theater.