In a statement distributed by the network, son Peter McCallum praised his father’s kindness and devotion to family, and his love of science and culture. “Somehow, even at 90, Daddy never grew old,” he said.
Mr. McCallum was a stalwart on “NCIS,” among the longest-running series on U.S. television. He joined the crime series when it launched in 2003, playing Donald “Ducky” Mallard, the Naval Criminal Investigative Service’s chief medical examiner, and remained a familiar face on-screen through to its 20th season this year.
In an oral history of “NCIS” published the day of Mr. McCallum’s death, insiders spoke to the Hollywood Reporter of his importance to the hugely popular show. Co-creator Donald P. Bellisario threatened to refuse to make it if Mr. McCallum wasn’t cast, according to director James Whitmore Jr.
“He was that serious about it,” Whitmore recalled. “The studio went with it, and of course, David McCallum is gold.” At 90, Mr. McCallum had scaled back his work with the show and was ready to retire, executive producer Charles Floyd Johnson told the publication.
In a joint statement distributed by CBS, “NCIS” executive producers Steven D. Binder and David North described Mr. McCallum as “a scholar and a gentleman, always gracious, a consummate professional, and never one to pass up a joke.”
Before “NCIS,” he was best known as Russian secret agent Illya Kuryakin in “The Man from U.N.C.L.E.,” a role that made him a 1960s heartthrob.
Partnered with Robert Vaughn’s Napoleon Solo, Kuryakin undertook various missions in international espionage against an evil organization that wanted to conquer the world. The show aired from 1964 to 1968, transitioning from black-and-white to color, and helped fuel a craze for spies and their exploits.
Mr. McCallum was recognized with two Emmy nominations for this part, and a third for the TV movie “Teacher, Teacher” in 1969.
He was born in Scotland in 1933 and, after school, was conscripted into the British military, where he served about two years, spending some of that time in Africa. He initially attended the Royal Academy of Music in London, specializing in the oboe, before switching to acting and studying at the Royal Academy of Dramatic Art, moving to the United States in his late 20s.
He accumulated dozens of film, television and theater credits over a long career, including in “The Great Escape,” “Sapphire and Steel,” and even a voice acting role in the children’s animated franchise “Ben 10.”
He released four 1960s albums of mostly instrumental jazz pop, including original compositions and covers. One track, “The Edge,” was famously sampled by Dr. Dre in 1999 for the song “The Next Episode,” featuring Snoop Dogg.
McCallum also published a crime novel, “Once a Crooked Man,” in 2016.