Sen. Daniel K. Inouye (D-Hawaii) passed away just after 5 p.m. this evening at Walter Reed National Military Medical Center, his office said.

His last word was “Aloha.”

Inouye, 88, was the longest-serving senator currently in the upper chamber. Chairman of the Senate Appropriations Committee, he was first elected in 1963. He was third in the line of presidential succession as president pro tempore of the chamber; Sen. Pat Leahy (D-Vt.) is expected to move into that role.

At the age of 17, he enlisted in the U.S. Army shortly after Imperial Japan attacked Pearl Harbor on Dec. 7, 1941.

He served with ‘E’ company of the 442 Regimental Combat Team, a group consisting entirely of Americans of Japanese ancestry. Inouye lost his arm charging a series of machine gun nests on a hill in San Terenzo, Italy, on April 21, 1945. His actions during that battle earned him the Medal of Honor.

Following statehood in 1959, Inouye served as Hawaii’s first congressman and would later be the first chairman of the Senate Intelligence Committee. His current Senate term was his ninth.

Inouye fainted on the Hill Dec. 6 and was taken to George Washington University Hospital. He was transferred to Walter Reed on Dec. 9.

The cause of death was cited as “respiratory complications.” His wife Irene and his son Ken were at his side. Last rites were performed by Senate Chaplain Dr. Barry Black.

When asked in recent days how he wanted to be remembered, Inouye said, “I represented the people of Hawaii and this nation honestly and to the best of my ability. I think I did OK.”

“Today, the Senate lost a true giant,” Sen. Lindsey Graham (R-S.C.) said. “Senator Inouye represented with distinction the Greatest Generation.”

“When he was still a soldier, recovering from the loss of an arm in combat, Senator Inouye learned about the Holocaust and began a lifelong attachment to the Jewish people and, later, to Israel,” Israeli Ambassador to the U.S. Michael Oren tweeted. “His dedication to Israel’s security was unswerving. Our people owe him an immense historic debt.”