Why can't Professor Xavier walk? Even the films can't keep their own answer straight
Why is Professor X in a wheelchair? The reason behind Charles Xavier's paralysis in the X-Men comics and films, how the two versions differ, and why the movie timeline keeps contradicting itself.
There are questions with clean answers, and then there are questions the X-Men franchise has answered four different ways whilst maintaining direct eye contact. "Why can't Professor Xavier walk?" is firmly the latter. The short version exists. The long version is a continuity crime scene.
The official answers, plural
- In the comics: an alien warlord named Lucifer — yes, really — crushes Charles's legs with a boulder in the Himalayas, as recounted in X-Men #20. Marvel has since healed and re-paralysed him more times than is polite to count.
- In the films: the beach in Cuba, 1962. At the end of X-Men: First Class, Magneto deflects a bullet straight into his best friend's spine. Tragic, elegant, character-defining.
- In Days of Future Past: 1973-era Charles is walking again, thanks to a serum that restores his legs at the cost of his telepathy. He eventually gives it up and returns to the chair. Fine. Sensible. A rule, even.

Where it all falls apart
The rule lasted about as long as a Summers brother's happiness. X-Men Origins: Wolverine shows Xavier strolling about in the late seventies; the Last Stand flashback has him upright and fully powered in 1986 — both impossible if the serum was binned in '73, as Collider's plot-hole ranking lays out. And that's before you touch Patrick Stewart's line in the very first film:
"When I was 17, I met a young man named Erik Lehnsherr."
Lovely delivery. Shame First Class has them meeting as fully grown adults over a decade later.
The filmmakers, to their credit, were never precious about it. When an interviewer pointed out to writer-producer Simon Kinberg that Charles was up and walking in Days of Future Past despite how the previous film ended, his entire response to Collider was:
"You're not mistaken."
Which is, frankly, the most honest thing anyone has ever said about X-Men continuity. The wheelchair is the point — the visual shorthand for the most powerful mind on Earth housed in a body that was betrayed by his closest friend. The films agree on that much. On everything else, they've agreed to disagree with themselves.