After passing the audition for the film produced by Haruki Kadokawa, she began her acting career. Along with teen idols Tomoyo Harada and Noriko Watanabe who debuted from Kadokawa Haruki Corporation, she was often dubbed as one of "Kadokawa Sannin-musume" in her early career.

Yakushimaru made her acting debut in the 1978 movie Never Give Up. In 1981, she came into prominence with Sailor Suit and Machine Gun, the film where she played the leading role. She also recorded the same-titled theme song for the film, which hit No. 1 on Oricon in late 1981, and stayed there until January 18, 1982.