Director - Michael Curtiz

The scene of Rick Blaine (Humphrey Bogart) putting Ilsa Lund (Ingrid Bergman) and Victor Laszlo (Paul Henreid) on a plane bound for America with the help of Captain Louis Renault (Claude Rains) is chock full of memorable lines but the line listed as 5th in AFI's 100 Years...100 Movie Quotes wasn't even part of the original script.
According to reports, Bogart said the phrase "Here's looking at you kid" multiple times to Bergman while teaching her to play poker between takes.