Americans know the story of Sen. Daniel K. Inouye the war hero, the senior appropriator, the president pro tem and the second-longest-serving senator in history.

But not everybody knew the Hawaii Democrat, who died Monday at age 88, as “Danny.”

That collegial intimacy is what resonated through the ceremony in the Rotunda on Thursday morning, where lawmakers, Cabinet members and staffers joined family and friends for the first in a series of memorial services planned for the late senator.

“Almost all of us who got to know him loved Danny,” Vice President Joseph R. Biden Jr. said in his eulogy. “How many of your colleagues can you say that about?”

In a casket draped with the American flag, Inouye was carried into the Rotunda about 10 a.m. by an honor guard, and his casket was placed on the historic catafalque constructed in 1865 for President Abraham Lincoln’s funeral.

Inouye will lie in state until Friday morning, when his body will be taken to the National Cathedral. Until that time, four Capitol Police officers in ceremonial attire will stand watch at all times, in shifts.

Senate Chaplain Barry C. Black, who administered last rites to Inouye at the Walter Reed National Military Medical Center in Bethesda, Md., delivered the invocation. Senate Majority Leader Harry Reid, D-Nev., and Speaker John A. Boehner, R-Ohio, also spoke.

“It’s proper that he should lie beneath the enduring symbol of democracy, the Dome of the Capitol,” Reid said. “Dan Inouye was an institution, and he deserves to spend at least another day in this beautiful building in which he dedicated his life.

“He leaves behind a legacy of public service and private kindness,” Reid said.

“While this may be a quiet ceremony for a quiet man, it will endure long after the respects are paid,” Boehner said. “For when this Rotunda comes back to life and the tour guides give their pitch, they will always speak of Daniel Inouye, the gentlemen from Hawaii and one of freedom’s more gallant champions.”

Biden’s eulogy was the most personal, drawing from the friendship he shared with Inouye, which predated Biden’s being sworn in to the Senate in 1973. Inouye campaigned for him, Biden said, and when Biden’s first wife and 1-year-old daughter were killed in a car accident just weeks after his election, Inouye stood by him.

“When I lost my family … he was one of the first of my future colleagues at my side, encouraging me to keep going,” Biden said. “It’s awful hard to look at a man with one arm, who’d been through all he’d been through, and he’s telling you to keep up, and you say, ‘No, no.’”

Looking to Inouye’s family, seated at his left, he said, “Your dad did more for me than you’ll ever know.”

Biden also spoke of Inouye’s unshakable integrity, the resolve of his character and of how his great professional success was due in part to moral compass.

“That … is the most valuable capital any man or woman who has ever served in this place can possess. And he had it from the outset,” he said.

Wreaths were placed on three sides of Inouye’s casket by Reid and Senate Minority Leader Mitch McConnell, R-Ky., by Boehner and House Minority Leader Nancy Pelosi, D-Calif., and by Biden. After a benediction by the House chaplain, the Rev. Patrick J. Conroy, the procession began for family and lawmakers to pay their respects.

Inouye’s wife, Irene Hirano, held the arm of a military officer as she approached the catafalque alone, in a somewhat private moment. He then led her around the curve of the Rotunda to accept the condolences of the senators who stood behind the rope barriers. She paused to speak with Sen. Barbara A. Mikulski, D-Md., who just Wednesday was tapped to succeed Inouye at the helm of the Appropriations Committee.

As the senators made their loop around the hall, led by Senate Sergeant-at-Arms Terrance Gainer, they passed House lawmakers who were grouped in a separate section.

Sen. Carl Levin, D-Mich., and his wife paused in front of the casket and put their arms around each other, and as they moved on they remained arm-in-arm.

And Sen. Daniel K. Akaka, D-Hawaii, who served with Inouye for two decades and who will retire at the end of this session, was walking as he normally does, slowly and bent over his cane. His eyes were wet and red-rimmed, but the 88-year-old lawmaker smiled as he shook hands with his friends from the other chamber.

He was trailed closely by his communications director, Jesse Broder Van Dyke, who was pulled into a hug by Rep. Colleen Hanabusa, D-Hawaii.

Many senators stopped to embrace Hanabusa. Before his death, Inouye asked Hawaii Democratic Gov. Neil Abercrombie to appoint her to his seat.

Pelosi took Hanabusa’s hand when it was House members’ turn to take their lap around the casket, led by House Sergeant-at-Arms Paul Irving.

Rep.-elect Tammy Duckworth, D-Ill., a war veteran herself, came to Washington for the ceremony and paused in her wheelchair to give a salute. Another veteran, outgoing Rep. Allen B. West, R-Fla., did so, too.

Later in the day, another old soldier and friend, former Senate Majority Leader Bob Dole, R-Kan., was led by Reid and McConnell into the Rotunda to say goodbye. Dole and Inouye met after World War II, when they were both recovering from grave injuries.