David McCallum hated this one thing about Mark Harmon on the ‘NCIS’ set – real reason revealed

Over the course of his long and very successful career, late actor David McCallum played a number of iconic characters.

With his parents being professional musicians, his dad, David Sr., worked as an orchestral violinist for the London Philharmonic Orchestra, his mother, Dorothy, as a cellist, everyone assumed McCallum would choose the same career path. Well, it’s not that he didn’t, because besides being a famous name in the film industry, he’s also a musician who released four albums with Capitol Records during the mid 60’s.

Speaking of his love for music, McCallum once said, “I always knew that I could turn to music if I failed as an actor.”

Acting, however, became his passion the moment he stepped on stage for the first time.

“I played The Little Prince in Shakespeare’s King John, at one of those local things where people do skits and songs. Mine was the little prince having his eyes put out by this terrible man, and I acted it, evidently, very well, because I got a standing ovation. I wasn’t more than eight,” he recalled.

“And I said: ‘Hey, hey, hey, this is kinda cool!’ I don’t know if I consciously thought it, but I had found the place I wanted to be: on a stage, with the lights and make-up and the people. I’m exactly the same to this day; the feeling has never left.”

Initially, he attended the Royal Academy of Music in London, England, but left it for the Royal Academy of Dramatic Art.

The Scottish born actor eventually left his home country in order to pursue an acting career in Hollywood. He had his breakthrough with the series The Man From U.N.C.L.E where he played secret agent Illya Kuryakin. For his incredible performance, he was nominated for two Emmy Awards.

His most recent role was that of quirky Dr. Donald “Ducky” Mallard in the hit series NCIS in which he played alongside Mark Harmon and Cote de Pablo.

Sadly, McCallum passed away on September 25, 2023.

“David was a gifted actor and author, and beloved by many around the world,” the NCIS tribute said.

“He led an incredible life, and his legacy will forever live on through his family and the countless hours on film and television that will never go away.”

McCallum once referred to NCIS as to his “Rock of Gibraltar,” mainly because of his working relationship with Mark Harmon. That feeling was mutual, to say the least.

“I’ll always remember David McCallum,” Harmon said in 2019. “And I thought that from day one here, because I thought how fortunate this entire cast, whoever it is, is lucky enough to work with him and watch his work ethic every day. And take from his experience, what he’s had in this industry, for a number of years, in different shows.”

Harmon played practical jokes on everyone on set, but not on McCallum. Why? Because he didn’t have the nerve to do so.

In early 2016, David McCallum set up an AMA (Ask Me Anything) thread on the popular social media platform Reddit. Among the rest, they asked plenty of question about the cast of NCIS.

One person wanted to know if Harmon ever played a prank on McCallum, to what the actor answered: “Mark Harmon knows I am not the type to be toyed with.”

Harmon appeared in his last episode as Leroy Jethro Gibbs on Monday, October 9, 2022. He left the show after starring in 435 episodes – 18 less than David McCallum.