Captain Ellerby is mostly just comic relief for most of this movie. But with the great comedic timing of Alec Baldwin, this character makes the most of his time in the sun, delivering classic lines like this one:
ELLERBY: I'm gonna smoke. You wanna smoke? You don't smoke? One of those fitness freaks, huh? Go f*** yourself.
When he's not sweating through his shirt and yelling at people, Ellerby is asking Colin about how things are going in his life. When Colin reveals that he doesn't care if a person is guilty or innocent as long as the cops get someone for a crime, Ellerby can only cynically answer:
ELLERBY: I think you are a cop, my son.
All of Captain Ellerby's best moments in this movie come when he's totally freaking out. When one of his camera techs fails to put cameras in the right places for a sting, Ellerby can only say:
ELLERBY: Did you put a camera in the back? Can I talk to you for a second, please?
As soon as he pulls the guy aside, he slugs him right in the face and accuses him of messing up a whole operation. At another point, Ellerby responds to Sergeant Dignam's tantrum by firing him on the spot, saying:
ELLERBY: World needs plenty of bartenders. Two weeks with pay.
Now you might be thinking that this movie doesn't really need Captain Ellerby. But the truth is that without his comic relief, the tone of the movie would be completely different—maybe even a little too much for some audiences.