Successful farmer and businessman, governor of Georgia, American president and Nobel Peace Prize winner: Jimmy Carter led a life that gave him status and power. But the 39th and longest-lived US president, who turns 100 on October 1, was never quite the insider that his successful resume would suggest.

It’s a reality obscured by many tributes that have come since Carter entered hospice care early last year, as the Democrat is praised not only for his longevity but also for his achievements in government and as a global humanitarian the decades following his departure from the White House in 1981.

“Jimmy Carter was always an outsider,” Jonathan Alter, his biographer, said in an interview.

In fact, Carter climbed the political ladder and fought against the establishment. He won in 1976 as a little-known former governor of Georgia, promising honesty and competence after the Vietnam quagmire and the Watergate scandal that toppled Richard Nixon. But neither in Atlanta nor in Washington did Carter wield the power that many politicians have.

Even 28 years after his humiliating defeat by Ronald Reagan, Carter was unable to secure an invitation to speak at the 2008 Democratic National Convention because a young candidate named Barack Obama feared any association with the president voters had rejected.

“It was still an epithet: ‘Another Jimmy Carter,'” David Axelrod, a top Obama adviser and confidant, told The Associated Press, calling it a “painful” decision for the future 44th president.

Carter’s identity as an outsider can be traced back to his earliest years, growing up on a farm outside his tiny hometown in south Georgia.

“He came from one of the wealthier families,” Alter noted, because James Earl Carter Sr. owned land that black sharecroppers farmed. “But when he went to school in Plains and was barefoot most of the year, the kids in town thought he was a country farmer.”

But it was this dichotomy that ultimately propelled Carter into the presidency.

As a young state senator, he sometimes defied party leaders. He did not join either the conservative segregationists or the racist progressives who together formed the Democratic Party in the South. He privately supported integration, but never met his fellow Georgian Martin Luther King Jr.

Carter won the governor’s office in 1970 as a racist moderate. In office, he angered some of his white supporters by opening state government to black contractors and appointees. He became close to King’s widow and his father. He also angered his former parliamentary colleagues by reorganizing the state government.

“He spent a lot of political capital making people angry and going after their fiefdoms,” said Terry Coleman, a Carter ally in the caucus.

When Carter decided to visit the Oval Office, he had only met a president—Nixon—briefly at a White House reception. The national media largely dismissed Carter’s chances against better-known figures, including several senators. But his appearance as an honest Baptist and peanut farmer fit the mood of voters.

Still, it wasn’t enough to navigate the country’s capital smoothly.

“His presidency was unique in that it came from completely outside the party establishment and then continued to operate that way in Washington,” said Joe Trippi, who worked for Massachusetts Sen. Ted Kennedy, scion of a Democratic dynasty and Carter’s eternal one Liberal rival.

Trippi noted that Carter largely avoided appointing veterans of the Roosevelt, Truman, Kennedy and Johnson administrations.

Obama, Reagan and certainly Donald Trump challenged the establishment as candidates, but ultimately absorbed their parties. As sitting president in 1980, Carter watched as congressional delegates gave Ted Kennedy a thunderous ovation, even after Carter won their painful primary campaign.

“The Democratic Party never belonged to Jimmy Carter,” Trippi said.

Nor did Carter dominate Capitol Hill, the national press corps, or the Washington social scene.

Amber Roessner, a Carter expert at the University of Tennessee, said he faced two obstacles: Congressional leaders did not view him as one of them, and the national media approached him with a regional bias against the South.

“Some members of the press,” Carter complained in an interview with Playboy magazine, “are treating the South as a suspect nation.”

Long after he left office, the U.S. Naval Academy graduate and engineer continued to lament a political cartoon published in conjunction with his inauguration that depicted his family with his mother, “Miss Lillian,” chewing on a hay seed White House approached.

In December 1977, when Carter’s team had been in the West Wing for less than a year, Washington Post columnist Sally Quinn called them “an alien tribe” incapable of “playing the game.” Quinn, herself an elite Georgetown hostess, nodded to Washington’s “frivolity,” even as she described “the Carter people” as “actually not comfortable in limousines or yachts or in elegant salons, in black tie” or with “place cards, servants , six courses, different forks, three wines… and a social gathering after dinner.”

Carter returned home in 1981 “humiliated by the voters” and “at least somewhat depressed,” Alter said, but had his most lasting success as an outside influencer when he and Rosalynn Carter founded the Carter Center in Atlanta in 1982.

Decades of global democracy and human rights advocacy followed. Some of the former president’s international maneuvers angered his successors and the Washington foreign policy establishment. Carter criticized the United States’ wars in the Middle East, the West’s isolation of North Korea and Israel’s treatment of Palestine. He also won a Nobel Peace Prize.

“The best way to understand Carter as an outsider is to see him as always understanding the rules of the insider circle,” Roessner said. “He just didn’t always play along.”