The Democratic National Committee (DNC) revealed its top priority after President Joe Biden announced Sunday he won’t seek reelection for president.

Democratic National Committee chairman Jaime Harrison said in a statement that Democrats will “undertake a transparent and orderly process to move forward as a united Democratic Party with a candidate who can defeat” former President Donald Trump, the Republican Party’s nominee for president, in the November election.

“This process will be governed by established rules and procedures of the party,” Mr. Harrison added. “Our delegates are prepared to take seriously their responsibility in swiftly delivering a candidate to the American people.”

His statement also said that “in short order, the American people will hear from the Democratic Party on next steps and the path forward for the nomination process.”

Unlike President Biden, Mr. Harrison did not endorse Vice President Kamala Harris to become the Democratic Party’s presidential nominee.

President Biden has signaled that he wants to serve out the remainder of his term in office, which ends at 12 p.m. ET on Jan. 20, 2025.

“It has been the greatest honor of my life to serve as your President. And while it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as President for the remainder of my term,” he wrote in a letter posted to his X account, announcing he’s dropping out.

Several top Democrats heaped praise on President Biden after his announcement that he will drop out of the 2024 presidential race, just a few months before the general election.

“President Biden has been an extraordinary, history-making president—a leader who has fought hard for working people and delivered astonishing results for all Americans,” wrote California Gov. Gavin Newsom on social media. “He will go down in history as one of the most impactful and selfless presidents. Thank you, [Joe Biden].”

Mr. Newsom has been speculated as a possible Democratic presidential candidate, though he has dismissed the notion when asked about it. He also has been one of the most high-profile surrogates of President Biden after the latter’s debate performance against former President Trump in late June.

The governor did not mention Ms. Harris, who President Biden officially endorsed on Sunday, in his social media post.

Another Democrat who has been speculated as a possible Democratic presidential candidate, Gov. Gretchen Whitmer of Michigan, said President Biden has been a “great public servant” before praising his record.

“His remarkable work to lower prescription drug costs, fix the damn roads, bring supply chains home, address climate change, and ensure America’s global leadership over decades will go down in history,” she wrote, adding that she will do “everything I can to elect Democrats.”

She also made no mention of Ms. Harris.

Senate Majority Leader Chuck Schumer (D-N.Y.) said that President Biden has been a “great president and a great legislative leader,” adding that “his decision of course was not easy, but he once again put his country, his party, and our future first.”

“Joe, today shows you are a true patriot and great American,” the Senate leader wrote.

Mr. Schumer’s deputy, Sen. Dick Durbin (D-Ill.), also said President Biden “always put country first,” adding, “Now the Democratic Party must unite behind a candidate who can defeat Donald Trump and keep America moving in the right direction. I will do everything in my power to help that effort.”

Not all Democrats appeared to be pleased with President Biden’s decision, including his former White House chief of staff, Ron Klain. However, Mr. Klain did endorse Ms. Harris.

“Now that the donors and electeds have pushed out the only candidate who has ever beaten Trump, it’s time to end the political fantasy games and unite behind the only veteran of a national campaign—our outstanding Kamala Harris’!! Let’s get real and win in November!” he wrote.