Then-New York Gov. Franklin Delano Roosevelt poses with two of his grandchildren, Anna Eleanor Dall, left, and Curtis Roosevelt Dall, in 1932. (AP)

Curtis, or “Buzzie,” as he was called, was 3 when his parents separated. So his mother moved back in with her parents, taking Buzzie and his older sister from New York to Washington.

Buzzie settled easily into his new surroundings. He got a lot of attention, not only from his doting grandfather but also from reporters and photographers whose coverage of their new home — at 1600 Pennsylvania Avenue — made the towheaded moppets instant media darlings of the 1930s.

Buzzie was formally Curtis Roosevelt Dall, the oldest grandson of President Franklin D. Roosevelt and first lady Eleanor Roosevelt. His sister was Anna Eleanor Dall, known as “Sistie.” And their highly choreographed, highly conspicuous adventures as “first grandchildren” living in the White House during the Depression generated myriad stories for a country in desperate need of escapism.

Minus the enviable curls, they were the Shirley Temples of Washington news coverage.

Buzzie — known as Curtis Boettiger after taking his stepfather’s surname for many years and then as Curtis Roosevelt soon after reaching adulthood — spent a lifetime wrestling with aspects of his identity.

Roosevelt grandchildren — “Sistie” and “Buzzie” Dall — at play on the White House grounds. (Harris & Ewing Collection/Library of Congress Prints and Photographs Division)

In a 2008 memoir, “Too Close to the Sun,” he wrote about the bewildering public adoration and scrutiny that followed him in childhood and the self-consciousness that followed him for decades of measuring up to such formidable grandparents.

He became an administrator in the United Nations Secretariat and retired initially to Majorca off Spain, where he made pottery, and ultimately to Southern France. He died Sept. 26 at 86 at his home in Saint-Bonnet-du-Gard, France. The cause was an apparent heart attack, said Michele Slung, his literary executor.

Buzzie, Sistie and their mother, also named Anna, lived at the White House from 1933, the year of his grandfather’s inauguration, until 1935. They remained frequent guests during the next decade, and it was again their home address when the president died in April 1945.

As Mr. Roosevelt later described it, his time at the White House was variously regimented and carefree. He saw it, as any child might, as a playground but with very serious people milling about. He liked to romp around the basement and its many unoccupied rooms.

He recalled hopping on his grandfather’s bed some mornings and having the president read the comics to him. “My grandfather seemed to savor the few moments of silliness,” he would write in his book.

He adored his paternal great-grandmother, Sara, who with Franklin “were the only two who made me feel loved.” They lavished affection. He was less enamored of the first lady, whom he found over the years to be distant, harshly judgmental and preoccupied with causes. He often called her a better grandmother to the world than to her own grandchildren.

Buzzie and Sistie were often trotted out for public ceremonies at the White House. They hosted a Christmas Party for 60 other children in 1933. At the 1934 Easter Egg Roll, Buzzie reportedly went agog when a magician known as Thurston pulled a live white rabbit from the child’s shirt. They had fleeting encounters with celebrities of the day, among them child star Shirley Temple.

Curtis Roosevelt, grandson of FDR, in 2008. (Helayne Seidman/For The Washington Post)

Articles were written when Buzzie and Sistie got colds or when they had a sip of champagne at a soiree. Balancing the frivolous coverage was an undercurrent of menace directed at such prominent youngsters.

Not long after the baby of aviator Charles Lindbergh was kidnapped and killed, Buzzie and Sistie were also the target of threats. A former Navy officer wrote an extortion letter to the first lady demanding that unless she gave him $168,000, he would harm the children. Haplessly and fortunately, he left a contact number and was soon arrested.

Buzzie found his life upended again in 1935 when his mother married John Boettiger, a former reporter who had just been named publisher of a Seattle newspaper.

Crestfallen to leave the White House, Curtis later said he felt like “a bit of a freak” in his new public school setting and was often lonely with two busy parents. He was eventually sent to a military school.

As Curtis Roosevelt — a name he took after his stepfather killed himself in 1950 — he served a stint in the Army and worked in advertising and public relations, among other jobs.

In 1964, around the time he received a master’s degree in government and public law at Columbia University, he switched to a civil service career in the United Nations. He spent two decades with the world body, focusing on strengthening ties to non-governmental organizations.

In the 1970s, he spearheaded an effort to preserve Eleanor Roosevelt’s Hyde Park, N.Y., cottage — and the surrounding property known as Val-Kill — from residential development. Now the Eleanor Roosevelt National Historic Site, it is managed by the National Park Service.

Curtis Roosevelt Dall was born in Manhattan on April 19, 1930. His father, Curtis Bean Dall, was a stockbroker. His mother was the only daughter of Franklin and Eleanor Roosevelt.

For much of his youth, Curtis Roosevelt was estranged from his father, who found a second calling on the political fringe. He spent decades at the head of the Liberty Lobby, an activist group that raised money for segregationist politicians and promoted anti-Semitic conspiracy theories. He also wrote a polemic called “F.D.R.: My Exploited Father-In-Law.”

Around the time he joined the U.N., Curtis Roosevelt told the New York Times he had a “cordial” relationship with his father, “even though our politics differ considerably.”

Mr. Roosevelt’s marriages to Robin Edwards, Ruth Sublette and Jeanette Schlottmann ended in divorce. In 1985, he married Marina Jones, who survives, along with a daughter from his first marriage, Julianna Roosevelt of Long Beach, Calif.; a sister, Anna Eleanor Seagraves of Bethesda, Md.; a half-brother, John Boettiger of Mill Valley, Calif.; and a grandson.

Mr. Roosevelt’s memoir appeared just as Barack Obama, the father of two young daughters, was elected president, and interviewers asked for his take on Obama’s children and what they might expect.

“I get the sense of two people who are good parents,” he told the Atlanta Journal-Constitution.

“The girls reflect that. The children are older than I was, which is better. . . . Although there is a lot of scrutiny already, it will be worse. The White House is, for lack of a better term, a goldfish bowl. It’s inevitable that they will be affected.”