Screen and television veteran Robert Stack, best known to audiences as Eliot Ness, the crimefighter on the popular series “The Untouchables,” died Wednesday at his home in Los Angeles. He was 84.

Stack had a varied film career. His matinee-idol looks brought him instant celebrity at age 20 when he gave the popular Deanna Durbin her second onscreen kiss, and he went on to cop a 1956 supporting actor Oscar nomination for Douglas Sirk’s “Written on the Wind.” He also excelled in comedies, from Ernst Lubitsch’s “To Be or Not to Be” to 1980’s popular spoof “Airplane.”

Though he had rarely acted of late, Stack’s sober, measured tones still resonated in the nation’s living rooms via the syndicated series “Unsolved Mysteries.”

Born of wealthy parents in Los Angeles, Stack was an avid sportsman in his teens, winning the World Skeet shooting championship by the age of 16; he would later be a top speedboat racer as well.

Educated at USC, he was approached to act while visiting a movie set. He had little formal training, which accounted for his somewhat wooden quality in his early films. What was touted then as Durbin’s first kiss in 1939’s “First Love,” was actually her second. But the publicity surrounding the buss made Stack instantly popular, and he next appeared in “The Mortal Storm” in 1940 and as Carole Lombard’s fling in “To Be or Not to Be,” the comedienne’s final role before her death in 1942.

After serving in the war effort as a Navy aerial gunnery instructor, he was assigned largely to juvenile roles in films like “A Date With Judy” and “Miss Tatlock’s Millions.”

By 1951 he’d clearly outgrown such vehicles, and Budd Boetticher gave him a true male lead in “The Bullfighter and the Lady,” in which his stoic, taciturn qualities were utilized to good effect. He had a brief run as a lead or second lead, appearing in “House of Bamboo,” “The Iron Glove” and opposite John Wayne in 1954’s “The High and the Mighty.”

But he excelled in supporting roles, as he demonstrated in “Written on the Wind,” as a drunken playboy opposite Rock Hudson, and in Sirk’s “The Tarnished Angels” in 1958, again with Hudson. He also played the title role in the biographical drama “John Paul Jones” that same year.

Then, in 1959, he turned to television and was an immediate hit as the imperturbable, driven, Prohibition Era crimefighter Eliot Ness in “The Untouchables,” which ran from 1959 to 1963 and brought him an Emmy in 1960.

Thereafter, most of his film roles were in foreign co-productions such as “Is Paris Burning?” and “The Story of a Woman” in 1969.

He would be identified as Ness despite a second hit series, “The Name of the Game” from 1968 to 1971, and other shorter-lived efforts such as “Most Wanted” in 1976-77, “Strike Force,” (’81-82) and hosting “Unsolved Mysteries” starting in 1991.

Along with Leslie Nielsen and Lloyd Bridges, also popular film/TV performers who had only abbreviated careers as leading men, Stack spoofed himself and the disaster movie genre in 1978’s “Airplane!” He then went on to comedic roles in films like “Caddyshack II” and “Joe Versus the Volcano” as well as a more serious role in 1983’s “Uncommon Valour.

In 1980 he published his memoirs, “Straight Shooting.”

Stack is survived by his wife, former actress Rosemarie Bowe, and two children.