Ren has strawberry blonde colored hair which reaches his shoulders, and his bangs go across his right eye. He has cool light blue eyes and usually wears his top two buttons down revealing a little of his chest. His way of clothing is usually loose and playful, giving him the flirty appearance. He has fawn tanned skin, and also one noticeable pierced ear, similar to that of Kurusu Syo's.
His child appearance had shorter hair and his ear was not pierced.
He is a flirtatious, adventurous and carefree person. Ren is known to be very famous among the ladies and never fails to charm them with his sweet talk. At times Ren is showed to be selfish but very passionate when it comes to music. He also gives nicknames to his bandmates. In addition, he seems to be introverted in the sense that he keeps his hardships to himself, until Haruka gives him the opportunity to speak openly.
Ren is the youngest child in the family, and his older brother forced him to go to Saotome Academy to become an idol and serve as the Jinguji family's tool for publicity. Ren indeed went to the academy, but during his stay he had no passion for music whatsoever. When he was still a child, Ren lost his mother due to an accident. He was only able to see his mother's face through recorded video tapes of her performances, and this revealed that Ren's mother was a famous idol. One day when Ren was watching his mother's tapes, his father came in and frantically discarded all of them, stating that he thought he threw away everything of her's. This caused Ren to believe that his father hated his mother. Grieving during his childhood with the loss of his mother, Ren would often go to the park and listen to his mother's singing through his mp3 player. The song he liked to listen to in particular was the song his mother hummed when she was carrying Ren during her pregnancy. He meets Nanami Haruka at Saotome Academy's gate entrance for the first time. It was when he saw her help a lost little girl find her mother at the park that he took interest in her and gave her the nickname "Little Lamb".