Marie Sinol was born in London, England to her mother Sinclair Sinol and Daniel Sinol. Her parents, both previous attendees of Hogwarts as a Slytherin and Ravenclaw respectively, had high hopes for their first born daughter to attend the school just as they had.

Her mother, Sinclair, currently works as an Auror under the Ministry of Magic. Her father, Daniel, works as an Obliviator under the Ministry of Magic as well. Both come from long lines of pure-blood wizards and witches who all have some history at Hogwarts, although such history is nothing of much importance in the grand scheme of events.

When they had Marie, Daniel was the one to take a leave from work to raise her, Sinclair being the working parent of the two. From a very early age, Daniel had begun to teach Marie basic literacy and mathematic skills, switching the education over to other basic academic subjects as she grew older. Prior to attending Hogwarts, Daniel had begun to teach Marie very basic charms in a controlled environment. Throughout most of this time, Marie's mother was absent. However, Sinclair finally took a part in her child's life at this point to also assist in Marie's early home-schooled education.

When Marie received an owl with the acceptance letter to Hogwarts, her parents bid her differing farewells—her father wished her to enjoy the experience to the fullest while her mother asked for her to make them proud.