The guitarist, who appeared early in the movie and at the Georges Méliès party near the end, was modeled after famed Belgian guitarist Django Reinhardt. The filmmakers even went so far as to have the actor's left-hand match Django's. He doesn't use his fourth and fifth fingers (which were burned in a fire).
Martin Scorsese and Sir Christopher Lee were excellent friends but, up until 2010, had never worked together. Lee's response when Scorsese asked him to appear in Hugo was: "It's about time!"
After a screening that James Cameron attended, he called this movie a "masterpiece" and told director Martin Scorsese it was the best use of 3-D he had seen, including his movies.
Sir Christopher Lee, having been born in 1922, makes him the only supporting actor to have lived in the age this movie is set: 1931.
In flashbacks, we see Georges Méliès staging his productions with lavishly colored sets and costumes. The real Méliès only used sets, costumes, and make-up in grayscale since colored elements might turn out the wrong shade of gray on black-and-white film. Many of the prints were then hand-tinted in post-production.
Brian Selznick: The book's author can be seen at the end of the movie at Méliès' apartment. He is wearing glasses, following behind Méliès and the film professor.
Michael Pitt: The star of Martin Scorsese's Boardwalk Empire (2010) has an uncredited appearance as the projectionist.
Martin Scorsese: The photographer who is taking a picture of young Georges Méliès outside his new studio and a minute later can be heard in Méliès' studio saying, "Good, that's good, yes."