Obama returns to White House to help Biden push Affordable Care Act

"It's good to be back at the White House," Obama said from the East Room.

For the first time since leaving office, former President Barack Obama returned to the White House on Tuesday to join his former vice president -- Joe Biden -- in promoting the Affordable Health Care Act he signed into law 12 years ago.

Obama joined Biden and Vice President Kamala Harris to deliver remarks on the Affordable Care Act, with Harris speaking first to applaud the anniversary and introduce the former president. Obama received a standing ovation and told a packed East Room, "It's good to be back at the White House."

Before addressing the landmark legislation of his presidency, Obama cracked a few jokes, as he often did as president, opening his remarks by thanking "Vice President Biden."

"That was a joke. That was all set-up," Obama said to laughter, walking back to give Biden a hug.

"I confess, I heard some changes have been made by the current president since I was last here," Obama continued. "Apparently, Secret Service agents have to wear Aviator glasses now. The Navy mess has been replaced by a Baskin-Robbins. And there's a cat running around, which I guarantee Beau and Sunny would have been very unhappy about," he said to laughter, referring to the Obamas' dogs.

The former president then pivoted to the purpose of his visit: to celebrate 12 years of the Affordable Care Act, saying it's "an example of why you run for office in the first place."

"We're not supposed to do this just to occupy a seat or to hang on to power. We're supposed to do this because it's making a difference in the lives of the people who sent us here," Obama said, before introducing Biden.

"My name is Joe Biden, and I'm Barack Obama's vice president," Biden said, prompting more laughter in the room. "It feels like the good old days -- being here with you brings back so many good memories."

"Let's be honest, the Affordable Care Act has been called a lot of things, but Obamacare is the most fitting," Biden added with apparent pride, "Obamacare."

He went on to announce new steps the Biden administration is taking to build on the Affordable Care Act, including a new executive order directing federal agencies "to do everything in their power" to expand coverage and make it easier to enroll, which he signed after his remarks, as well as a proposed rule from the Treasury Department to fix the ACA's so-called "family glitch."

"Once today's proposed rule is finalized, starting next year, working families in America will get the help they need to afford full family coverage," Biden said. "With this change, it's estimated that 200,000 presently uninsured Americans are going to gain coverage. Nearly one million Americans will see their coverage become more affordable."

Biden also urged Congress to take action to keep the expansions his administration has put in place under the American Rescue Plan intact and pitched to Americans to keep up the fight to prevent Republicans from trying, again, to repeal the ACA.

"If Republicans have their way, it means 100 million Americans with pre-existing conditions can once again be denied health care coverage by their insurance companies. That's what the law was before Obamacare. In addition, tens of millions of Americans could lose their coverage, including young people who will no longer be able to stay on their parent's insurance policy until age 26," Biden said.

"We need to keep up the fight," he added, calling out the GOP for its "unrelenting" campaign against the ACA.

Biden went back to poking fun at himself before signing the executive order, recalling back to when he was caught on hot mic back in 2010 telling Obama the ACA was "a big f****** deal."

"And Barack, let me remind you -- it's a hot mic,” Biden said to laughter.

Previewing Tuesday's remarks, White House press secretary Jen Psaki said Monday that Obama and Biden would also have lunch at the White House Tuesday -- "as they used to do on a weekly basis" -- and added, "They continue to talk regularly."

"They are real friends, not just Washington friends, and so I'm sure they will talk about events in the world as well as their families and personal lives," Psaki said.

The visit from the popular former president comes as Biden struggles in the polls over his handling of 40-year-high inflation and soaring gas prices he's pinned to the ongoing war in Ukraine.

Psaki said it's "exactly the right time to have the former president come here -- given this is one of the proudest accomplishments that they worked on together, they shared together."

"And it is emblematic of their shared view and belief that government can work for people and it can work for the American people. And this is an example of building on a success from more than 10 years ago and making it better over time," she added.

Psaki also said to expect Obama to return to the White House again soon for his presidential portrait unveiling "and perhaps other engagements here in the future," she said.

Since Biden took office, the administration helped to lower health care premiums for nine million Americans through the American Rescue Plan, Psaki noted Monday, "the biggest expansion of affordable health care since the ACA."

"We've made affordable health coverage more accessible during the pandemic through the opening of the special enrollment period, which enabled nearly three million Americans to have access to newly sign up for coverage under the ACA," she said. "And President Biden has overseen the most successful open enrollment in history last year with the historic 14.5 million Americans signing up for ACA coverage and another million people signing up for the basic health care program."

Tuesday marked Biden and Obama's first joint appearance since attending the 20th anniversary of the Sept. 11 attacks last fall in New York and their first joint event in Washington since Biden's inauguration in January 2021.

When the pair celebrated the ACA's passage 12 years ago last month, Biden was caught on hot mic applauding Obama at the White House for what he called "a big f------ deal."

Paraphrasing the memorable moment, a senior administration official told reporters, on what Biden announced, "to borrow a phrase, this rule is a -- is a big deal."

"We think it's the most significant administrative action to improve implementation of the ACA that we've taken since the law was first implemented," the official added.

The rule would begin to take effect beginning Jan. 1, 2023, and Americans will be able to sign up to get financial assistance during the next open enrollment period.

As of last year, about 31 million Americans had health care coverage through the ACA, according to the Department of Health and Human Services.

ABC's Karen Travers reports:

ABC News' Molly Nagle and Justin Gomez contributed to this report.