She got scouted in her homeplace, Osaka, and entered the entertainment industry. While belonging to the office in which she got scouted, she participated in EXILE's dance competition and started to attend the famous academy EXPG, studying both dancing and singing.
In October, it was decided that she would become a member of the unit Happiness among other EXPG students, and her official stage name became KAREN.
In February, she began her modeling career by becoming an exclusive model to the magazine nicola.
On February 9, she made major debut with Happiness with their single "Kiss Me".
On April 24, she was announced as member of E-girls, having a concurrent position between the group and Happiness.
In May, her work as an exclusive model of nicola ended.
On June 3, she changed her stage name and started using her birth name.
In January, she made her debut as actress on the TV drama Koibumi Biyori.
In February, she was the cover of the April issue of JJ, being her first magazine cover since her debut as a model.
On December 31, Shuuka graduated from Flower and ShuuKaRen and retired from entertainment business. With Karen being the only remaining member of the duo, ShuuKaRen has disbanded.
- Main article: List:Fujii Karen Discography Featured In
-  HiGH&LOW THE MOVIE
- Main article: Fujii Karen/Gallery
- Hobbies: Singing, doing her nails
- Talent: Dancing
- Favorite Food: Fruit, plums, octopus
- Favorite Brands: 24karats, INGNI, ANAP
- Goal: To be an artist who can sing and dance
- She started an Instagram account on November 24, 2017.
|Trivia · Category · Happiness songs template|
|Current Members||SAYAKA · Kaede · Fujii Karen · MIYUU (Leader) · YURINO · Suda Anna · Kawamoto Ruri|
|Former Members||MIMU · Sugieda Mayu|
|Albums||1. Happy Time · 2. GIRLZ N' EFFECT|
|Singles||Indie: Happy Talk|
|Digital Singles||1. POWER GIRLS|
|Concerts & Tours|
|Tours||1. GIRLZ N' EFFECT|
|Concerts Featured In||E-girls: COLORFUL LAND · COLORFUL WORLD · E.G. SMILE · E.G.EVOLUTION|
E.G.family: E.G.POWER 2019 ~POWER to the DOME~
|Units & Other Acts|
|Associated Acts||E-girls · ShuuKaRen · Sudannayuzuyully|