ATLANTA (AP) — Jimmy Carter reached his 100th birthday Tuesday, the first time an American president has lived a full century and the latest milestone in a life that took the son of a Depression-era farmer to the White House and across the world as a Nobel Peace Prize-winning humanitarian and advocate for democracy.

Living the last 19 months in home hospice care in Plains, the Georgia Democrat and 39th president has continued to defy expectations, just as he did through a remarkable rise from his family peanut farming and warehouse business to the world stage. He served one presidential term from 1977 to 1981 and then worked more than four decades leading The Carter Center, which he and his wife Rosalynn co-founded in 1982 to “wage peace, fight disease, and build hope.”

“Not everybody gets 100 years on this earth, and when somebody does, and when they use that time to do so much good for so many people, it’s worth celebrating,” Jason Carter, the former president’s grandson and chair of The Carter Center governing board, said in an interview.

“These last few months, 19 months, now that he’s been in hospice, it’s been a chance for our family to reflect,” he continued, “and then for the rest of the country and the world to really reflect on him. That’s been a really gratifying time.”

James Earl Carter Jr. was born Oct. 1, 1924 in Plains, where he has lived more than 80 of his 100 years. He is expected to mark his birthday in the same one-story home he and Rosalynn built in the early 1960s — before his first election to the Georgia state Senate. The former first lady, who was also born in Plains, died last November at 96.

President Joe Biden, who was the first sitting senator to endorse Carter’s 1976 campaign, praised his longtime friend for an “unwavering belief in the power of human goodness.”

“You’ve always been a moral force for our nation and the world (and) a beloved friend to Jill and me and our family,” the 81-year-old president tells Carter in a tribute video filmed in front of Carter’s presidential portrait at the White House.

Outside the North Portico, the Bidens are placing a display of large lettering declaring “Happy Birthday President Carter” and the number 100. Carter has asked Biden to eulogize him at his state funeral when the time comes.

The Carter Center on Sept. 17 hosted a musical gala in Atlanta to celebrate the former president with a range of genres and artists, including some who campaigned with him in 1976. The event raised more than $1.2 million for the center’s programs and will be broadcast Tuesday evening on Georgia Public Broadcasting.

In St. Paul, Minnesota, Habitat for Humanity volunteers are honoring Carter with a five-day effort to build 30 houses. The Carters became top ambassadors for the international organization after leaving the White House and hosted annual building projects into their 90s. Carter survived a cancer diagnosis and treatment in his early 90s, then several falls and a hip replacement in his mid-90s before announcing at 98 that he would enter hospice care.

Townspeople in Plains planned another concert Tuesday evening.

The last time Jimmy Carter was seen publicly was nearly a year ago, using a reclining wheelchair to attend his wife’s two funeral services. Visibly diminished and silent, he was joined on the front row of Glenn Memorial United Methodist Church in Atlanta by the couple’s four children, every living former first lady, Biden and his wife Jill and former President Bill Clinton. A day later, Carter joined his extended family and parishioners at Maranatha Baptist Church in Plains, where the former president taught Sunday School for decades.

Jason Carter said the 100th birthday celebrations were not something the family expected to see once his grandmother died. The former president’s hospital bed had been set up in the same room so he could see his wife of 77 years and talk to her in her final days and hours.

“We frankly didn’t think he was going to go on much longer,” Jason Cater said. “But it’s a faith journey for him, and he’s really given himself over to what he feels is God’s plan. He knows he’s not in charge. But in these last few months, especially, he has gotten a lot more engaged in world events, a lot more engaged in politics, a lot more, just engaged, emotionally, with all of us.”

Jason Carter said the centenarian president, born only four years after women were granted the constitutional right to vote and four decades before Black women won ballot access, is eager to cast his 2024 presidential ballot — for Vice President Kamala Harris, the Democrat who would become the first woman, second Black person and first person of south Asian descent to reach the Oval Office.

“He, like a lot of us, was incredibly gratified by his friend Joe Biden’s courageous choice to pass the torch,” the younger Carter said. “You know, my grandfather and The Carter Center have observed more than 100 elections in 40 other countries, right? So, he knows how rare it is for somebody who’s a sitting president to give up power in any context.”

Jason Carter continued, “When we started asking him about his 100th birthday, he said he was excited to vote for Kamala Harris.”

Early voting in Georgia begins Oct. 15, two weeks into Carter’s 101st year.