The Rise of Skywalker's US sales were down nearly 30% on the first movie in the saga, The Force Awakens.
Still, the latest instalment ranked as one of the best December openings in North America.
It is expected to end a strong year for distributor Disney, with a string of hits grossing more than $1bn.
Starring Daisy Ridley and John Boyega, the film is the final chapter in the Skywalker saga begun by George Lucas in 1977. It is set one year after its predecessor.