Mark Harmon Pays Heartfelt Tribute to 'NCIS' Co-Star David McCallum Following His Death

Mark Harmon feels "honored" to have worked with his longtime NCIS co-star David McCallum, who died Monday at age 90. The actor, who played Special Agent Leroy Jethro Gibbs opposite McCallum's Dr. Donald 'Ducky' Mallard for nearly 20 years before exiting the CBS procedural in 2021, praised his former castmate in a statement to TVLine. 

"David lived a great, full, long life," Harmon told the outlet. "I was in awe when I first met him and all of us on the show were honored to have toed a mark opposite him. My condolences go out to Katherine and his family." McCallum, who also starred as Illya Kuryakin in the hit '60s spy drama The Man From U.N.C.L.E., most recently appeared remotely in the final two episodes of NCIS Season 20 last spring.

Monday, the actor passed away at New York Presbyterian Hospital of natural causes. He is survived by four children and his wife of 56 years, Katherine McCallum. Following his death, son Peter McCallum issued a statement, calling his dad "the kindest, coolest, most patient and loving father," and "a true renaissance man." Peter continued, "He was fascinated by science and culture and would turn those passions into knowledge. For example, he was capable of conducting a symphony orchestra and (if needed) could actually perform an autopsy, based on his decades-long studies for his role on NCIS."

The CBS star was also remembered by NCIS' current executive producers, Steven D. Binder and David North. "For over 20 years, David McCallum endeared himself to audiences around the world playing the wise, quirky, and sometimes enigmatic, Dr. Donald 'Ducky' Mallard," they said in a statement. "But as much as his fans may have loved him, those who worked side by side with David loved him that much more. He was a scholar and a gentleman, always gracious, a consummate professional, and never one to pass up a joke. From day one, it was an honor to work with him and he never let us down. He was, quite simply, a legend. He was also family and will be deeply missed."

A CBS spokesperson added in an additional statement, "We are deeply saddened by the passing of David McCallum and privileged that CBS was his home for so many years. David was a gifted actor and author, and beloved by many around the world. 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. We will miss his warmth and endearing sense of humor that lit up any room or soundstage he stepped onto, as well as the brilliant stories he often shared from a life well-lived."