Composer Stephen Sondheim, notoriously protective of his stage works, long resisted offers to film this story. When Tim Burton expressed interest, however, Sondheim relented when pleased with Burton's vision for the project, and on the condition that the composer would maintain casting approval. Burton would only agree to direct with Johnny Depp in the lead, and though Sondheim feared Depp's vocals would be too "rock oriented," the composer approved the actor after a vocal audition. To approve the casting of Helena Bonham Carter, and to combat any rumor of nepotism (as Carter and Burton were romantically involved), the actress sent Sondheim no less than twelve audition tapes of her singing. Very impressed with her vocals, Sondheim immediately approved the actress. Also, in his 2010 book about his career as a songwriter, "Finishing the Hat," Sondheim states this is the only adaptation of one of his works for the screen for which he approves.

At the start of the film, as Todd's ship arrives, a completed Tower Bridge is seen. Construction of Tower Bridge started in 1886 and it wasn't completed until 1894, at least 50 years after the film is set.

It is raining during the opening credits. Some of the raindrops can be seen to actually be blood. The blood shortly morphs into more substantial form, showing itself to be integral to parts of what we will later see is Sweeney Todd's murderous machinery of revenge and madness.

The final act in the US version uses different angles than the International version of the film during some extra violent deaths. The different angles focus more Sweeney instead of the immense amounts of blood that can be seen more vividly in the International cut. All in all it only amounts to around 3-5 seconds that are actually different and were needed in order to get the R-Rated in the US.

Edited into 5 Second Movies: Sweeney Todd Part 2 (2010)