Carl Sack is a fictional character on the television series Boston Legal, played by John Larroquette. Carl is one of the main characters in Boston Legal after being introduced in the fourth season.

Carl once described himself as "wild" growing up, and that his parents thought he was a problem. He revealed to Shirley Schmidt that his mother died as a result of medical malpractice due to blood thinners. He previously spent time in the New York offices of Crane, Poole, and Schmidt before moving to the Boston office at Shirley's request to help rein in Denny's excessive behavior.

Carl was startled at the conduct of the Boston branch of the firm and did not have an easy time transitioning to the atmosphere of the office. He was particularly surprised at the carefree antics of Denny Crane and Alan Shore. He spent several episodes fruitlessly attempting to control Denny's behavior and deal with the bizarre cases that frequently ran through the Boston office of the law firm.

Carl was an old flame of Shirley's, and they embarked on a more serious relationship. Carl admitted his apprehension about falling in love with her given how fast she had gone through other men. In "Thanksgiving" he formally proposed to Shirley, and she accepted.

Initially Carl thought he did not belong at the Boston office, and midway through the fourth season he considered returning to New York City. Shirley talked him out of it, saying he was needed at the Boston offices and saying she needed him. Since then Carl has grown more accustomed to the offices and realizes that the atmosphere is exactly where he wants to be, once admitting that he "loves this place".

Throughout his time as a partner of the Boston firm, Carl has served as both Denny's handler and rival. In addition to representing Denny twice in court cases, Carl has occasionally butted heads with Denny, sometimes over Shirley. They once bet on whether or not Carl could win a case involving a Mexican defendant who hosted cockfights in his house, to Shirley's dismay. Carl has grown accustomed to Denny's antics and even takes part in them, once bantering back and forth during Denny's trial for concealing a firearm and pushing the judge to a breaking point.

Despite his rivalry with Denny, Carl does show him respect for what he has achieved during his career. When Denny threatens to take his name off the firm's title if Jerry does not make partner, Paul Lewiston claims that Denny no longer has any weight at the firm, while another administrative partner suggests that they could rid themselves of Denny, by ignoring his request to make Jerry a partner, claiming that Denny has become a liability. Carl is the only one to come to Denny's defense, pointing out that his name is on the door. This implies that Carl still sees Denny as a great asset to the firm.

Template:Boston Legal