Xavier's son Legion (David Charles Haller) has vast psionic powers like his father but also suffers from severe mental illness, including multiple personality disorder.

Cassandra Nova, a parasitic life form born bodiless on the astral plane, began life at the same time as Charles Xavier. She improvised a body by copying Xavier's DNA, effectively becoming his twin sister. She grew with her brother inside their mother's womb until Charles sensed her monstrous thoughts and attempted to kill the creature, resulting in its physical body being stillborn.

Xavier uses his ancestral mansion at 1407 Graymalkin Lane as a base of operations for the X-Men.

Xorn heals the X-Men of a nano-Sentinel infection, restoring Professor Xavier's ability to walk in the process, but later reveals himself to be Magneto. After revealing himself, Magneto reverses the repairs to Xavier's legs, kidnaps him, and destroys the X-Mansion.

Dr. Brian Xavier was a well-respected nuclear scientist.

Xavier's family lived in a mansion estate in Westchester County because of the riches his father's nuclear research had brought them.