WASHINGTON — Growing up in Queens, Robert S. Trump learned to survive in the shadow of a rambunctious older brother, Donald, who monopolized attention. In adulthood, his older brother was his boss at the Trump Organization. And near the end of his life, he became his older brother’s defender, joining him in publicly excoriating their niece, Mary, who had written a memoir about life inside a family she characterized as cold and cruel.
On Friday, President Trump repaid Robert, the brother who had always been loyal, by hosting a funeral in the East Room of the White House. Robert Trump died last week in New York at 71. The White House did not give a cause.
It was the first time a president has held a funeral for a family member in nearly 100 years, according to the White House Historical Association. Mr. Trump delivered the eulogy, which lasted about 10 minutes. The guest list was limited to about 150 people, including the president’s eldest son, Donald Trump Jr., and his girlfriend, Kimberly Guilfoyle, as well as an extended network of relatives.
Other guests included Representative Peter T. King, Republican of New York, who posted his invitation on Twitter. Vice President Mike Pence and Rudolph W. Giuliani, the former mayor of New York, also attended.
Guests did not wear masks at the funeral, but they were given coronavirus tests beforehand at the Trump International Hotel.
The White House declined to comment on details because it was a private service, although Mr. Trump eventually allowed reporters to view part of the closing funeral procession. The president, accompanied by the first lady, Melania Trump, and followed by his younger sister, Elizabeth Trump Grau, trailed pallbearers down the steps of the North Portico as the hymn “Abide With Me” was played on bagpipes. Several of Mr. Trump’s other children, including Barron and Ivanka, looked on.
The president’s allies said they were not surprised that Mr. Trump chose to host his brother’s funeral at the White House.
“Robert Trump, along with his wife, Ann Marie, were allies, supporters and defenders of President Trump,” said Eric Bolling, a conservative media personality, who was invited but unable to attend the service.
Robert and Ann Marie Pallan were married this year, more than a decade after he ended his marriage to Blaine Trump. They lived on Long Island, where Robert was often seen at local bars boasting about his brother.
The president was keenly aware of the accolades. “He was my biggest fan,” Mr. Trump said on “Fox & Friends” this week. “People would tell me all the time, ‘I spoke to your brother, and your brother was so thrilled.’ And so thrilled at what was happening.”
In “Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man,” Mary L. Trump, a clinical psychologist and Mr. Trump’s only niece, recounts how the two brothers worked together in an effort to cut her inheritance and health benefits from a family trust. Ms. Trump, the daughter of Fred Trump Jr., Mr. Trump’s older brother who died in 1981, describes Robert Trump as the enforcer.
Robert defended his brother in July, when Ms. Trump’s book was published.
“I and the rest of my entire family are so proud of my wonderful brother, the president, and feel that Mary’s actions are truly a disgrace,” Robert Trump said in a statement.
While several presidents, including John F. Kennedy and Abraham Lincoln, have lain in state in the East Room, the largest room in the White House, it is unusual to have a funeral there for a president’s relative.
White House officials said that Mr. Trump would pay for the funeral expenses, and that his brother’s body was driven from New York for the funeral on Friday.
“It’s clearly not something we’ve seen often,” said Anita McBride, a board member of the White House Historical Association and the chief of staff to Laura Bush when Mrs. Bush was first lady. “But this is their family home that we loan to them to use while they are in office.”
Most funerals at the White House for first family members have been for children. Among them were Calvin Coolidge Jr., President Calvin Coolidge’s son who died at 16 in 1924 of a blood infection caused by a blister on his foot, and Willie Lincoln, Lincoln’s son who died at 11 in 1862 of typhoid. Willie Lincoln was embalmed in the Green Room, and his funeral service was held in the East Room. Ms. McBride noted that although Robert Trump did not live in the White House, “President Trump felt like this was a way he could honor his brother.”
The president’s own comments about the service were brief. “Robert, I Love You,” he wrote on Twitter. “Rest in Peace!”
Katie Rogers reported from Washington, and Maggie Haberman from New York.