Dean began attending Hogwarts School of Witchcraft and Wizardry in 1991 and was Sorted into Gryffindor house. Since he believed his stepfather was his biological father and Regulus never told Dean's mother he was a wizard, Dean grew up believing he was a Muggle-born. Dean became best friends with Seamus Finnegan, a half-blood Gryffindor, and was rarely seen away from him. He joined the Gryffindor Quidditch team as a Chaser and later joined the multi-house Phenomenal Phoenixes Quidditch team as a backup Chaser, which was captained by Harry Potter at the height of his unification of Hogwarts. Dean took to honing his skills as an artist in his downtime, creating several stunning pieces that were hung in the Gryffindor common room. He was part of Harry's Court, the circle of friends of Harry Potter. He dated Parvati Patil, a fellow Gryffindor student whom he took to the Winter Ball, but the pair broke up around their fifth year. During his sixth year, Dean began dating Ginny Weasley, another fellow Gryffindor in the year below him. During his seventh year, Dean took part in an apprenticeship with a famous painter.
After graduating from Hogwarts, Dean continued his apprenticeship full-time and became a well-known artist within Britain. He married Ginny Weasley in 2001 and with her, had two children; Nathan Seamus and Layla Luna Thomas.