According to Clint Eastwood biographer Marc Eliot, Stirling Silliphant suggested Tyne Daly for her role, but the actress turned down the script three times before finally deciding on doing it. Daly also suggested that the romantic attachment between her character and Callahan be omitted. Eastwood agreed.When Harry is about to intervene in the convenience store siege, his partner DiGiorgio (John Mitchum) asks if he needs help, but Harry responds that he 'may need to move fast and doesn't need too much linguini slowing him down'. This is a reference to Dirty Harry (1971), when DiGiorgio cannot climb over the fence with Harry to get into the football stadium due to his weight, with the excuse "Too much linguini." As with other movies in the Dirty Harry series, Callahan makes use of a repeated catchphrase. In Dirty Harry (1971) there was the "Do you feel lucky?" speech, in Magnum Force (1973) there was "Man's got to know his limitations", in Sudden Impact (1983) there was "Go ahead; make my day" and in The Dead Pool (1988) there was "You're shit out of luck". In this film, Callahan repeats the phrase "You can count on that/it" twice and the word "Marvelous" (sarcastically) four times. 

After Pauline Kael gave a bad review of the film, Clint Eastwood asked a psychiatrist to do an analysis of her from her reviews of his past work, which he had memorized verbatim. It concluded that Kael was actually physically attracted to Clint and because she couldn't have him she hated him. Therefore, it was some sort of vengeance according to Clint. [per Sondra Locke's autobiography].