Kubert, who passed away Sunday in Morristown, had multiple myeloma.
Kubert began illustrating comic books as a teenager in the 1930s, was associated with DC Comics for much of his career and was still drawing while in the hospital before his death, The New York Times reported.
"He's the longest-lived continuously important contributor to the field," Paul Levitz, a former president of DC Comics, told the Times Monday. "There are two or three of the greats left, but he's definitely one of the last."
Among the comic book figures Kubert is known for are World War II infantryman Sgt. Rock, crime fighter Hawkman, prehistoric hero Tor, and Mr. Kanigher, Enemy Ace.
He also wrote and illustrated graphic novels about war such as "Fax From Sarajevo" (1996), "Yossel" (2003) and "Dong Xoai" (2010).
"For me, it was not about war and fighting but about the people, the characters," Kubert told The (Cleveland) Plain Dealer in a 2003 interview.
Kubert was born in a village that was part of Poland at the time and is now in Ukraine. He emigrated to the United States with his family as an infant and grew up in New York's Brooklyn borough.