[citation needed] Although she voluntarily applied for the audition and passed, she was still looking at then-AKB48 project in a suspicious way, and tried to skip the very first dancing lesson because of her then-part-time job, but eventually participated it in response to the persuasion by Tomonobu Togasaki, Manager of AKB48 Theater.

Kojima made her first appearance on Kohaku Uta Gassen, an annual music show where the most successful artists of the year are invited, with AKB48 on December 31, 2007.

[4] Since 2007, Kojima has been actively exploring a possible acting career, and has made several appearances in a number of dramas and movies.

Additionally, Kojima made her first appearance on the silver screen in the horror movie Densen Uta (伝染歌), along with several fellow AKB48 members.

She expanded her brand by launching "Her lip to Beauty", "House of Herme", and "Rosier by HLT" in 2022.