The parts of Roxie and Velma were based on real people whose murder trials took place in 1924. Beulah Annan was the real life Roxie and Belva Gaertner was the real life Velma. Billy Flynn's real life counterpart was famed Chicago Shyster, W.W. O'Brien.
The storyline had to be changed in this version in order to placate the Hays Commission code; both the silent (Chicago (1927)) and modern (Chicago (2002)) versions are more faithful to the original 1926 play.