As 39th president of the United States, Jimmy Carter remains proud of his administration’s efforts and accomplishments during his four years in office in the late 70s. But, as the 92-year-old told Oprah during an interview for OWN’s “SuperSoul Sunday,” it’s actually his post-presidential years that have been most gratifying.

“When I was president of the most powerful and influential nation on earth, I had more total influence over peace and progress and things like that,” Carter acknowledges in the above clip. “But the last 35 years since I’ve left the White House has been the most challenging and interesting and adventurous and unpredictable and gratifying times of my life.”

Through the nonpartisan Carter Center, both the former president and first lady have focused fiercely on human rights, working to advance peace and health worldwide.

“We’ve dealt with literally millions of individual people in the tiny villages all over the world, and we treat people for diseases,” Carter explains.

Though this aspect of the Carters’ work has been credited with helping to practically eradicate Guinea worm disease, the former president’s legacy in the White House has been debated, particularly with reference to the much-televised hostage crisis of 1979-1980 and the slow recovery of the U.S. economy following the mid-70s recession. Given the harsh judgment and the fact that the Reagan era emerged after Carter’s presidency, Oprah asks the moderate Democrat how he looks back on his time in Washington.

“With gratitude and, I’d say, an adequate modicum of satisfaction,” Carter says. “In this book [A Full Life], I describe the things that we actually accomplished for good. That won’t be reversed. And the things that I tried and didn’t quite accomplish because of change in circumstances and so forth. But, I did the best I could. As my vice president said, ‘We told the truth, we obeyed the law and we kept the peace.’”

Original air date: Sept. 27, 2015

“SuperSoul Sunday” returns with new episodes this spring.

Another presidential reflection: