Happy birthday, Mr. President!

Former President Jimmy Carter became the first president to turn 100 years old Tuesday – and celebrated the milestone with family and friends as he was wheeled out to his backyard in his Georgia hometown.

A frail-looking Carter was surrounded by more than a dozen loved ones as he watched a military flyover held in his honor that involved four Navy F-18 jets, according to video from CBS, marking his first public appearance since his wife’s funeral in November 2023.

Carter was assisted by an aide as he watched, remaining still in his reclined wheelchair.

The occasion was marked by an outpouring of support for the centenarian, including birthday salutations from President Biden as well as former presidents George W. Bush, Bill Clinton and Barack Obama, which were shared by the Carter Center Presidential Library.

The Atlanta-based presidential library also dropped its admission fee to $1 (100 cents) as a nod to its namesake, and will be the site of the first of 101 trees to be planted to honor Carter’s legacy of environmentalism.

The center also hosted a star-studded birthday benefit concert last month, featuring performances by acts like Angelique Kidjo, BeBe Winans, the B-52s and the Atlanta Symphony Orchestra Chamber Chorus. 

The event raised more than $1.2 million for the center’s international programs and will air Tuesday on Georgia Public Broadcasting.

Carter’s hometown of Plains, Georgia threw its own party for the 39th president, complete with a concert and a flyover.

At the White House, the North Lawn was adorned with a giant golden “100” featuring the message “Happy Birthday President Carter.”

Born on Oct. 1, 1924, the soft-spoken peanut farmer was elected president of the United States in 1976, facing headwinds at every turn including energy shortages, Cold War drama and the Iran hostage crisis during his tenure as commander-in-chief.

Though his single term in office was marked by upheaval and uncertainty both domestically and abroad, Carter achieved numerous significant triumphs during his presidency, including brokering the historic Camp David peace accords in which Israel and Egypt officially recognized each other’s governments.

After serving as both Senator and governor of Georgia, Carter sought the Democratic nomination for president in 1976, running as a centrist reformer at a time when the country was still grappling with a crisis of confidence in government following the Watergate scandal.

Carter and running-mate Walter Mondale of Minnesota defeated incumbent President Gerald Ford by a margin of 297 to 241 electoral votes.

“I’ll never tell a lie. I’ll never make a misleading statement. I’ll never betray the confidence that any of you had in me. And I’ll never avoid a controversial issue,” he vowed at the time.

Carter’s administration came at a time when the US was wading through an economic quagmire brought on by the OPEC-induced gas crisis of the early 1970s. The era was marked by stubbornly elevated inflation, high unemployment, and stagnant demand — famously termed “stagflation.”

Then dueling crises in 1979 helped shape perceptions of his administration.

On Christmas Eve that year, Russia invaded Afghanistan, which prompted Carter to withdraw US participation from the 1980 Summer Olympics in Moscow.

A month earlier, Iranian students mobbed the US embassy in Tehran, taking 52 Americans hostage and holding them captive for 444 days.

A failed 1980 rescue effort that led to the deaths of eight US service members kneecapped Carter’s credibility on national security matters heading into a bruising primary, where he faced a challenge from within his own party courtesy of the late Democratic Sen. Ted Kennedy.

Carter would ultimately lose by a landslide to Ronald Reagan, 44 states to 6, in one of the biggest margins of defeat in US election history.

After leaving office, the longest-living president devoted himself to humanitarian and charitable endeavors, perhaps most famously his multi-decade commitment to Habitat for Humanity — which provides housing for the poor — and the Carter Presidential Center to promote human rights.

In 2002, Carter was awarded the Nobel Peace Prize “for his decades of untiring effort to find peaceful solutions to international conflicts, to advance democracy and human rights, and to promote economic and social development.”

“Just about everybody agrees Carter’s post-Presidency was the most productive in history. As one Carter opponent once told me, ‘What he is doing now [after the White House] almost makes enduring his years as president worth it,’” Larry Sabato, head of the University of Virginia’s Center for Politics, told The Post.

Carter wrote a remarkable 32 books in his lifetime, his most recent being “Faith: A Journey for All,” published in 2018, which emphasizes the importance of spirituality in his life and on American history.

He celebrated his 98th birthday in 2022 by attending a parade thrown in his honor in his hometown, where he lived in the same house with his wife, former first lady Rosalynn Carter, since 1961.

In February of last year, the Carter Center announced the former president had decided to receive hospice care at home rather than “additional medical intervention” following a “series of short hospital stays.” He remains under hospice care to this day.

Rosalynn joined her husband in hospice care that November, passing away two days after her condition was made public.

“Rosalynn was my equal partner in everything I ever accomplished,” Jimmy Carter said in a statement. “She gave me wise guidance and encouragement when I needed it. As long as Rosalynn was in the world, I always knew somebody loved and supported me.”

At 100 years old, Carter has long outlived his closest rival as the longest-living ex-president — former President George H.W. Bush died in November 2018 at the age of 94.

Former Presidents Ronald Reagan and Gerald Ford both passed away at the age of 93, while John Adams and Herbert Hoover lived to age 90.