Jimmy Malone: He pulls a knife, you pull a gun. He sends one of yours to the hospital, you send one of his to the morgue. That's the Chicago way!
When Eliot Ness is at Jim Malone's house for the first time, Malone's collar is opened, then buttoned, then open again.
Andy Garcia was originally brought in to read for Frank Nitti, but he asked if he could play George Stone instead.