Mr. Leiber, known as Gus, was noted for energetic, lyrical and colorful paintings, which he continued to create into his 90s.
“He was a true modernist, experimenting with form and technique and exploring Abstract Expressionism alongside the artists who would go on to define the movement, like de Kooning and Pollock,” said Jess Frost, associate curator of Guild Hall, the entertainment, arts and education center in East Hampton, N.Y.
Ms. Frost, who had cataloged the Leibers’ work at their museum, added, in a telephone interview, “He shifted easily between styles and was fearlessly committed to a new body of work that at times was altogether different from what he had been doing a year earlier.”
Mr. Leiber’s paintings ranged from abstract landscapes to representational, if stylized, fashion figures — some of which Ms. Leiber used for her handbag designs. He also made prints and sculptures.
In 2014, Mr. Leiber showed some of his later paintings in an exhibition at the Carter Burden Gallery on West 28th Street in Manhattan.
“It’s very rare to paint for 70 years, every day, which is what he did,” Marlena Vaccaro, the gallery’s director, said in a telephone interview. “His skill level, his commitment to the process of painting, was an inspiration. He kept his creative flow going and did not repeat the past. His paintings had a vital and beautiful quality to them.”
Mr. Leiber called the paintings in the show “the summation of a long search for clarity, honesty and beauty.”
His works are in the collections of the Metropolitan Museum of Art, the National Gallery of Art in Washington and the Whitney Museum of American Art, among other museums.
Mr. Leiber was born in Brooklyn on Nov. 12, 1921. His family — including his mother, Rebecca, and his father, William, a junk dealer — moved to Titusville, in northwest Pennsylvania, when he was a boy.
While in school he developed an interest in art, but his hopes of becoming an artist were limited by his family’s poverty; to help make ends meet he worked as a soda jerk and newspaper delivery boy. After working as a printer at the local newspaper, he entered the Army and was assigned to its Signal Corps.
Sergeant Leiber was stationed in North Africa and Italy before he was sent to Budapest as World War II was ending. There, in 1945, he met Judith Peto, who had begun selling her unusual handbags and purses to American soldiers.
In their first encounter, on a street in Budapest, he invited her to attended the opera. She later told him that her family had a room to rent to a military officer.
“She knew nothing about how the U.S. military made housing decisions,” Mr. Leiber told The New York Times last year. “She did, however, speak excellent English. I couldn’t find her a tenant, but I did fall in love.”
Recalling their courtship, he told The New York Post last year that he brought the Peto family “a few gifts of large cans of chicken from the mess hall.”
Judith Peto encouraged him to attend art school, where his talent thrived. They married in early 1946 and immigrated soon after to the United States.
When the couple visited his family in Titusville — home to a 19th-century oil boom — Mr. Leiber asked his mother where she had put the drawings of nude models he had sent her from Budapest. She had burned them all, she replied, because “they were immoral.”
The Leibers soon headed to New York, where he enrolled in the Art Students League, coming under the influence of the painter Will Barnet. He also studied engraving at the Brooklyn Museum Art School. Ms. Leiber designed handbags to support him while he was in school, and years later he urged her to open her own company.
“It sounds romantic,” Ms. Frost said, “but they shared a mind.”
Mr. Leiber, who is survived by a brother, had said that he and his wife were fulfilled without having children. Their children “hang on walls and from arms and shoulders,” he told The Times in 1970, adding, “As a couple we felt complete and still do.”