Koike has also been involved in various charity and promotional activities throughout her career. She has served as an ambassador for several Japanese brands and has supported a range of charitable causes, including organizations dedicated to promoting Japanese culture and supporting women's rights.

In addition to her music career, Koike also began to explore her passion for acting. She made her acting debut in 2013, appearing in the Japanese television drama, "Gaku Koshien." Her performance earned her recognition, and she went on to land roles in several other Japanese dramas and films, including "Nightwalk: The Midnight Detective" and "Chihayafuru."