[1][2][3] McCoy is introduced as Executive Assistant District Attorney by Adam Schiff (Steven Hill) in the season five premiere episode "Second Opinion".

In 2022, he appeared as the DA in the revival of the original Law & Order, with ADAs Nolan Price (Hugh Dancy) and Samantha Maroun (Odelya Halevi) working under him.

In the episode, a case in which a politically connected tech billionaire is charged with murdering a woman he had raped years earlier earns McCoy the enmity of New York City Mayor Robert Payne (Bruce Altman), who threatens to destroy his career and those of Nolan and Maroun unless they back off from calling his son as a witness, which would reveal the younger Payne's extramarital affairs.

McCoy prosecutes the case himself and obtains a guilty verdict; he then resigns as DA so the governor will appoint an interim successor, thus denying the vindictive Payne the chance to run him out of office and replace him with a lackey who would fire every ADA on his staff.

[14] In one episode, he mentions that Rebecca (Jamie Schofield) has taken a job in San Diego, and that she drove up to Los Angeles to meet him there for dinner while he was attending a conference on official business.

[18] The ADAs with whom McCoy had affairs included Sally Bell (Edie Falco), who later became a defense attorney;[19] Diana Hawthorne (Laila Robins); and Claire Kincaid (Jill Hennessy).

In the episode "Thrill", in which two teenaged boys are accused of killing a man for fun, McCoy finds his case particularly complicated when one of the suspects confesses the crime to his uncle, a priest.

"[25] Entertainment Weekly television critic Ken Tucker has praised Law & Order's creator Dick Wolf for putting McCoy at the center of "some of the best episodes of the immortal series' 19th season.

"[26] According to Tucker, riding herd "over a couple of stubborn young bucks — assistant DAs Mike Cutter (Linus Roache) and Connie Rubirosa (Alana de la Garza) — McCoy argues, bellows orders, and croaks with outrage when his charges disobey his legal advice".