George W. Bush shed a sentimental tear. President Barack Obama mused about the burdens of the office. Bill Clinton dished out wisecracks, and Jimmy Carter and George H.W. Bush chimed in, too.
A crowd of 10,000 attended the event, including Dick Cheney, Condoleezza Rice, Colin Powell and Karl Rove.
Politics took a back seat for the special event. There was no mention of Iraq or Afghanistan, the wars that dominated Bush's presidency and so divided the nation. There were only gentle references to the aftermath of Hurricane Katrina and plenty of praise for the resolve that Bush showed in responding to the 9/11 terror attacks.
It was a day for family and sentimentality. Bush choked up with emotion at the conclusion of his remarks.
The 43rd president singled out his 88-year-old father, another ex-president, to tell him: "41, it is awesome that you are here today."
The elder Bush spoke for less than a minute from his wheelchair, then turned to his son and quipped, "Too long?" He has a form of Parkinson's disease and has been hospitalized recently for bronchitis.
Just as the public tends to view presidents more kindly once they've left office, ex-presidents, too, tend to soften their judgments - or at least their public comments - with time.
Mr. Obama once criticized Bush for his "failed policies" and "disastrous" handling of the economy, for expanding budget deficits, and for drawing the nation into war in Iraq.
But Thursday, he instead praised Bush for his strength after 9/11, compassion in fighting HIV/AIDS in Africa, bipartisanship in pursuing education reforms and restarting "an important conversation by speaking with the American people about our history as a nation of laws and a nation of immigrants."
The other presidents took a similar tone.
Clinton praised Bush for his efforts to combat AIDS in Africa, his work on global health and even for the paintings he's doing in retirement.
Carter praised Bush for his role in helping secure peace between North and South Sudan in 2005 and the "great contributions you've made to the most needy people on earth."
Bush has kept a low profile since leaving office with an approval rating of just 33 percent. That number has since grown and is now at 47 percent, which is about equal to Mr. Obama's approval rating, according to a Washington Post-ABC News poll released ahead of the library opening.
Although politics wasn't center stage, those in attendance included a number of potential candidates for president in 2016 - another Clinton (Hillary) and Bush (Jeb) among them.
Though George W. Bush has supported the idea of his younger seeking the White House, former first lady Barbara Bush apparently does not feel the same.
"We've had enough Bushes," she said Thursday on NBC's "Today" show.
The presidential center at Southern Methodist University includes a library, museum and policy institute. It contains more than 70 million pages of paper records, 200 million emails, 4 million digital photos and 43,000 artifacts. Bush's library will feature the largest digital holdings of any of the 13 presidential libraries under the auspices of the National Archives and Records Administration.
A full-scale replica of the Oval Office as it looked during Bush's tenure sits on the campus, as well as a piece of steel from the World Trade Center and the bullhorn that Bush used to punctuate the chaos at ground zero three days after 9/11.
The Bush family's Texas roots are on full display at the library. Architects used local materials, including Texas Cordova cream limestone and trees from the central part of the state, in its construction.
The Associated Press contributed to this report.