This Feb. 6, 2006, photo shows Joe Kubert, life-long cartoonist and founder of the Joe Kubert School of Cartooning and Graphic Art, at his drawing table at the school in Dover, N.J. (Mike Derer/Associated Press)

Joe Kubert, the influential comic book artist and writer whose rugged, hyper-masculine artwork included Tarzan, the flying super-hero Hawkman, the World War II infantryman Sgt. Rock, and graphic novels about the Bosnian war and the Holocaust, died Aug. 12 at a hospital in Morristown, N.J. He was 85.

A spokesman at Mr. Kubert’s comic trade school, the Dover, N.J.-based Kubert School, confirmed the death and said the cause was multiple myeloma.

Mr. Kubert, whose career spanned more than seven decades, started in comic books during the industry’s infancy as a boy prodigy. He was perhaps best known for the two war comics he co-created for D.C. Comics with writer Robert Kanighter, Sgt. Rock and Easy Company, as well as Enemy Ace. By the standards of most 1960s comic books, typically marketed to preteen and teenage boys, the books were uncommonly grim and realistic.

Sgt. Rock, a strapping and stoical soldier, made his first appearance in 1959. His haggard platoon, Easy Company, always triumphs over seemingly impossible odds despite the soldiers’ physical and mental exhaustion.

Enemy Ace, which debuted in 1965, featured the adventures of Hans von Hammer, a chivalrous World War I German flying ace who often mourns for the fliers he kills in aerial combat.

Mr. Kubert was a master of crosshatching, a technique that uses closely drawn parallel and crossed lines. He routinely inked his own pencils, which made his work immediately recognizable and distinct from the assembly line approach of other comic book illustrators.

“Joe was one of the most important artists to ever work in comics, as evidenced just by the vast number of other artists who started off copying his work, learning from his work and — for a lucky group — attending his school,” comics writer Mark Evanier said. “He drew with intensity and testosterone and a sense of drama, and somehow made it look easy and impossible in every panel.”

Mr. Kubert, an Edgar Rice Burroughs fan, convinced D.C. to lease the character of Tarzan from the writer’s estate for an unusually faithful interpretation derived from the original novels in the early 1970s.

Although he freelanced for comic companies, Mr. Kubert was mostly associated with D.C. ,where he held an executive position beginning in 1967. He left his editorial duties at D.C. to open the Kubert School in 1976, an accredited trade school for comic book artists. Alumni of the school included noted artists John Totleben, Steve Bissette, Timothy Truman, Rick Veitch and Tom Mandrake.

In later decades, Mr. Kubert returned to war stories — or antiwar stories, as he preferred — with a series of graphic novels. “Fax From Sarajevo” (1996), a nonfiction work, recounted a family’s attempt to flee war-torn Bosnian. “Yossel April 19, 1943” (2003) was about a Jewish boy during the Holocaust and his involvement in the Warsaw ghetto uprising.

For Mr. Kubert, who was born in a Polish shetl, “Yossel” had personal significance. “I wondered what my life would have been like if they had stayed,” he told the Cleveland Plain Dealer. “In many ways, ‘Yossel’ is my story, my ‘what if’ story.”

Joseph Kubert (pronounced CUE-bert) was born Sept. 18, 1926, in Yzeran in what was then Poland and now part of Ukraine. He came to the United States as an infant and was raised in Brooklyn, where his father worked was a kosher butcher. His mother ran a restaurant, and the family lived in rooms in the back.

After the youngster started using his father’s butcher paper to draw, his father bought him a drawing table for $10 — a princely sum for the poor family. By his teens, Mr. Kubert was working in the production shop of cartoonist Will Eisner, creator of the Spirit.

His wife, Muriel Fogelson Kubert, who helped start the Kubert School, died in 2008. Survivors include five children; three sisters; 12 grandchildren; and a great-grandchild.

Two of Mr. Kubert’s sons, Andy and Adam, are both comic book artists. At the time of his death, Mr. Kubert was collaborating with Andy Kubert on the “Before Watchmen: Nite Owl” comic for D.C.

Michael Cavna contributed to this report.