Bull stars Michael Weatherly as Dr. Jason Bull in a drama inspired by the early career of Dr. Phil McGraw, the founder of one of the most prolific trial consulting firms of all time. Brilliant, brash and charming, Dr. Bull is the ultimate puppet master as he combines psychology, human intuition and high tech data to learn what makes jurors, attorneys, witnesses and the accused tick. Bull employs an enviable team of experts at Trial Analysis Corporation to shape successful narratives down to the very last detail. They include his quick-witted former brother-in-law, Benny Colón, a lawyer who acts as defense attorney in the company's mock trials; Marissa Morgan, a cutting-edge neurolinguistics expert from the Department of Homeland Security; former NYPD detective Danny James, the firm's tough but relatable investigator; haughty millennial hacker Cable McCrory, who is responsible for gathering cyber intelligence; and Chunk Palmer, a fashion-conscious stylist and former All-American lineman who fine tunes clients' appearances for trial. In high-stakes trials, Bull's combination of remarkable insight into human nature, three Ph.D.'s and a top-notch staff creates winning strategies that tip the scales of justice in his clients' favor.
When Bull joins the district attorney in a case against Kara Clayton, who claims she killed her billionaire husband in self-defense, tensions run high when he learns that his on-again, off-again romantic interest, Diana Lindsay, is defending the widow. Also, Chunk makes a decision about his future.
The DA's office asks Bull to assist them in their prosecution of a fraternity when a pledge accidentally drowns during a hazing incident, but his efforts may be derailed when the students close ranks to stonewall him.
Bull agrees to help the parents of a former employee sue a drug company when their son commits suicide during a drug trial. However, the task is complicated when the company brings in their own trial scientist, Arti Cander.
As Thanksgiving approaches, Bull releases his team to enjoy the holiday with their families, only to find himself working a case solo when he agrees to help a boxer who is being tried for murder. Also, Chunk makes a major personal decision at his family's Thanksgiving dinner, while Marissa's dinner with Kyle is abruptly cancelled when he is mugged.
As Christmas approaches, Bull is amused when he meets a 9-year-old girl who wants to hire him to help her divorce her parents, but he's shocked when a judge appoints him her temporary guardian. Also, Marissa discovers disturbing information about her boyfriend, Kyle.
Bull represents Jemma Whitbeck, a teenager arrested for robbing a jewelry store with an older man she disappeared with 18 months ago. To persuade the jury she is not guilty, Bull argues that Jemma was actually a victim of his abuse and manipulation and not his willing accomplice.
Bull takes a psychologist friend, Dr. Donovan Benanti, as a client when the therapist is sued for malpractice following a patient's deadly rampage. As Bull worries a trial loss could set new precedent regarding doctor-patient confidentiality, he aims to convince the jury that clinicians aren't directly responsible for their patients' actions.
Bull is brought on to help the FBI's case against a hacker whom they believe breached air traffic control at LaGuardia Airport. But when Cable learns that the accused is her friend's husband, she risks breaking the law – and defying Bull – to try and prove his innocence.