A defensive coordinator is typically a coach on a gridiron football team who is in charge of the defense. Generally, along with his offensive counterpart, he represents the second level of command structure after the head coach. The defensive coordinator is generally in charge of managing all defensive players and assistant coaches, of developing a general defensive game plan, and of calling the plays for the defense during the game. At higher levels of football (college and professional), the defensive coordinator typically has a number of assistant coaches working under him; usually coaches primarily responsible for the various defensive positions on the team (such defensive line, linebackers, or defensive backs).
The greatest Defensive Coordinator in NFL History is arguably Dick LeBeau, current defensive coordinator of the Pittsburgh Steelers. Throughout his span from 2004-current in Pittsburgh, the Steelers have ranked 1st on points 16.7 per game, passing yards with 189.8 per game, rushing defense 88.6 yards per game, total yards per game with 278.4 yards, and 1st in sacks with 408 sacks since he came to Pittsburgh