Nicolai Cikovsky Jr., a former curator at the National Gallery of Art. (Photo by Dennis Brack/Black Star/Dennis Brack/Black Star )

Nicolai Cikovsky Jr., an art historian who became a curator at the National Gallery of Art, where he took a leading role in organizing several major exhibitions, including a 1995 retrospective of the works of painter Winslow Homer, died May 1 at his home in Washington. He was 83.

He had colon cancer and leukemia, said his wife, Sarah Greenough, the National Gallery’s senior curator of photography.

Dr. Cikovsky, whose father was a painter, developed an interest in 19th-century American art as a student and became a leading authority on such painters as Homer, William Merritt Chase, George Inness and Samuel F.B. Morse — who also invented the telegraph.

After teaching at several colleges, Dr. Cikovsky joined the National Gallery of Art in 1983 as curator of American art. He was instrumental in acquiring many important paintings for the museum, including Homer’s “Home Sweet Home,” Albert Bierstadt’s “Lake Lucerne,” Georgia O’Keeffe’s “Black White and Blue” and works by Asher B. Durand, Rembrandt Peale, William Harnett and Childe Hassam, among others.

As a curator, Dr. Cikovksy was credited with greatly expanding public interest in American art. He was responsible for many celebrated exhibitions at the National Gallery, including shows devoted to Chase, Inness, James McNeill Whistler, Thomas Eakins and photographer Ansel Adams.

One of his most memorable exhibitions, curated with Franklin Kelly, was the 1995 retrospective showcasing a wide range of paintings, watercolors and drawings by Homer, a somewhat reclusive New England artist who lived from 1836 to 1910. On “CBS Sunday Morning,” Dr. Cikovsky pronounced Homer “surely the greatest American artist of the 19th century.”

It took more than five years to plan the Homer exhibition. Dr. Cikovsky and Kelly negotiated with other museums and with private owners around the world to obtain loans of Homer’s art. They considered more than 1,000 works before choosing the 245 that went on view.

“We traveled intensely for two years,” Dr. Cikovsky told the New York Times. “Then we took a break to see what we had. Then we traveled again.”

The curators also prepared a lavishly illustrated 420-page catalogue, which Washington Post art critic Paul Richard wrote was “certain to become a standard text on Homer’s life and pictures.”

The blockbuster exhibition was seen by more than 345,000 people at the National Gallery before traveling to the Metropolitan Museum of Art in New York and the Boston Museum of Fine Arts.

“We’ve had in-depth shows on French artists like Degas and Manet,” Dr. Cikovsky told The Post in 1996. “It was time for an American artist to have that kind of treatment, and Homer is one of those who really deserve it. His work is a reflection of us as a culture and as a nation.”

In a review in the New Republic, novelist John Updike said the exhibition was “one to make an American proud.”

Nicolai Cikovsky Jr. was born Feb. 11, 1933, in New York City. His father, who was born in Poland and studied in Russia, came to the United States in the 1920s and had a distinguished career as a painter of landscapes, portraits and still lifes.

Dr. Cikovsky was a 1955 graduate of Harvard University, where he also received master’s and doctoral degrees in art history in 1958 and 1965, respectively. He taught at Skidmore College in Saratoga Springs, N.Y., Pomona College in Claremont, Calif., and Vassar College in Poughkeepsie, N.Y., before joining the faculty of the University of New Mexico in 1974.

Before coming to the National Gallery, he published books on Inness and Morse, as well as several exhibition catalogues. When he retired from the National Gallery in 2002, Dr. Cikovsky held the title of senior curator of American and British painting.

His first marriage, to Thelma O’Brien, ended in divorce. Survivors include Greenough, his wife of 37 years, of Washington; a daughter from his first marriage, Emily Hilbert Cikovsky of Los Altos, Calif.; a daughter from his second marriage, Sophia Greenough Cikovsky of San Francisco; and two grandchildren.

In addition to organizing exhibitions and writing dozens of articles, books and catalogues, Dr. Cikovsky was an early proponent of technology as a tool for solving the puzzles of art history. He used infrared film to reveal how Inness, a 19th-century artist known for his landscapes, often painted over earlier versions of his work, sometimes dramatically changing the subject matter.

While examining Homer’s “Breezing Up” with infrared technology, Dr. Cikovsky discovered that the artist had significantly altered his painting of a sailboat scudding in choppy waters. Homer eliminated other boats from the painting, as well as the figure of a boy, substituting an anchor in his place.

“That he removed a boy and added on an anchor — a 19th-century symbol of hope,” Dr. Cikovsky told The Post in 1986, “suggests he intended the painting to convey a sense of optimism.”

“If you can see an artist doing something, you’ve caught him in his tracks,” he added. “You can then ask why. Why did he make this change?”