Grace Cartelet, wife of Mr. Cartelet and mother of Alice Cartelet, possesses long, curly pale-blonde hair typically secured in a low ponytail by a brown bow, featuring short bangs and curled forelocks, along with bright green eyes. Her appearance strongly resembles her daughter's, though she has a more developed physique. She often adorns a pale blue dress with a white frilled apron.

Grace exhibits a kind, caring, and friendly personality, treating others with maternal warmth, though she can display a temper when provoked. She communicates fluently in both Japanese and English. Her relationship with Alice is close and affectionate, maintained through regular letters. She treated Shinobu Omiya kindly during Shinobu's homestay in England and considers Karen Kujō like a second daughter due to Karen's long friendship with Alice.

A significant aspect of her background involves her college years in England, where she met and became close friends with Shinobu's mother. This friendship led to Shinobu's homestay with the Cartelet family and later facilitated Alice's stay with the Omiya family in Japan. Despite the distance, Grace and Mrs. Omiya sustain their friendship through technology like video calls. Old photos reveal their past connection during student days in England, and they reconnect via a FaceTime call in the present day.