David McCallum captured the hearts of NCIS fans as Dr. Donald “Ducky” Mallard, but his journey to joining the show was almost derailed before it began.

The Scottish actor, who played the beloved chief medical examiner from the series’ backdoor pilot until his passing in 2023, initially faced resistance from studio executives. According to former NCIS director James Whitmore Jr., producer Don Bellisario had to fight to keep David on board.

“When they cast David McCallum as Ducky, the studio said, ‘No way, we’re not casting this old character actor in the role,’” Whitmore revealed in an interview with The Hollywood Reporter. Bellisario, however, stood firm. “Don said, ‘If you don’t, we’re not doing the show.’ He was that serious about it. The studio went with it, and of course, David McCallum is gold.”

Peter Golden, CBS’s former head of casting, speculated that the studio’s hesitation stemmed from David’s British heritage. “I think it was because David McCallum was British. The feeling was, ‘Can you do that?’ This was such an American show,” he explained.

David himself once reflected on the process of landing the role. After being invited to meet casting director Bonnie Timmermann and audition for the pilot, he eventually met with Don Bellisario. “Afterwards, Don came out, put his arm around me, and said, ‘David,’” he recalled during an appearance at The Television Academy Foundation. “That’s when I realized I might have the charm they were looking for.”

The moment he learned he’d secured the role is one David never forgot. While fixing a flat tire in Los Angeles, he received the call with the good news. Laughing, he later remarked, “I said, well then, I’m gonna go get a car that works.”

Following David’s death in 2023, NCIS paid tribute to both the actor and his iconic character in an episode titled The Stories We Leave Behind, which explored one of Ducky’s unresolved cases. Executive producers Steven D. Binder and David North also released a heartfelt statement, praising David’s legacy:

“For over 20 years, David McCallum endeared himself to audiences around the world playing the wise, quirky, and sometimes enigmatic Dr. Donald ‘Ducky’ Mallard. But as much as his fans loved him, those who worked side by side with David loved him even more. He was a scholar and a gentleman, always gracious, a consummate professional, and never one to pass up a joke.”

David McCallum’s legacy as Ducky remains an integral part of NCIS history—a testament to his charm, talent, and the unwavering belief of Don Bellisario in his casting.