Why did Abby leave NCIS? The on-screen farewell was only half the story
Pauley Perrette played forensic scientist Abby Sciuto from before NCIS was even a show — she debuted in the 2003 JAG backdoor pilot — through the end of season 15 in May 2018. Her farewell episode drew roughly 14 million viewers. On screen, Abby's exit was tidy. Off screen, it was anything but.
What happened on the show
In the season 15 episodes "One Step Forward" and "Two Steps Back," Abby and MI6 agent Clayton Reeves are attacked by a hitman — and Reeves dies protecting her. After recovering, Abby resigns from NCIS to honor him by starting a charity in London. She says goodbye to the whole team except one person: her final moment with Gibbs is a note, which Mark Harmon's character reads while Abby watches from across the street.
The two actors never shared the screen in her last scene. That detail turned out to matter.
What Perrette said
When the exit was announced in October 2017, Perrette wrote on social media that the decision had been made a year earlier and batted away tabloid theories — no, she wasn't launching a skin care line, and no, the network wasn't mad at her.
In 2019, responding to constant questions about a return, she went further, posting about "multiple physical assaults" and writing that she was "terrified of Harmon" and had nightmares about him. She has said repeatedly she will never go back to the show.
What the producers said
The fullest account from the show's side arrived in The Hollywood Reporter's 2023 oral history for the series' 20th anniversary. Executive producer Charles Floyd Johnson traced the rift to an incident involving Harmon's dog:
"The dog was Harmon's, and apparently the dog bit someone," Johnson told The Hollywood Reporter in 2023.
Johnson described Perrette as a devoted animal-welfare advocate who felt the dog's continued presence on set wasn't safe — and said that by the end of that year, she felt the job was no longer working for her. Harmon, who stayed on NCIS until 2021, has never publicly detailed his side.
What happened after
Abby's lab went to Kasie Hines, played by Diona Reasonover, who remains on the show. Perrette starred in the CBS sitcom Broke, then announced her retirement from acting in 2020 after its cancellation. She has stayed on good terms with CBS and many former castmates.