White House chief of staff Ron Klain expected to step down in the coming weeks

White House chief of staff Ron Klain is expected to announce he is departing the administration in the coming weeks, according to two sources familiar with the decision.

The exact timeline is not set but a search for a replacement is underway, and it is expected that Klain will stay in the administration to help with the transition of his replacement.

Sources said it was expected that Klain would depart the White House after the midterm elections and discussions were ongoing about timing his departure around the administration's two-year anniversary.

The White House declined to comment.

The New York Times was the first to report on Klain's expected departure.

President Joe Biden named Klain to serve in the influential position just days after his 2020 victory. Biden said at the time that Klain's "deep varied experience and capacity to work with people all across the political spectrum is precisely what I need" in the administration.

When he was appointed White House chief of staff, Klain said it was the "honor of a lifetime."

The two have a decades-long relationship that spans back to the 1980s when Biden was a U.S. senator. Klain had been chief counsel when Biden led the Senate Judiciary Committee, including during the controversial 1991 Clarence Thomas-Anita Hill hearings.

He also worked on Biden's 1988 and 2008 presidential bids, and was a senior advisor on his 2020 campaign.

Klain served as Biden's chief of staff for two years during his vice presidency, and Biden credited him for helping to resuscitate the economy in the wake of the 2008 recession. Klain left the administration for the private sector in 2011 but later returned when he was tapped to lead the Obama administration's response to the Ebola health crisis in 2014.

Klain brought that experience into the Biden administration as it made COVID-19 and the economy two of its top priorities.

Klain marked the two-year mark of Biden's presidency on Jan. 20 by touting the administration's work on job creation, vaccine distribution, the appointment of federal judges -- including Ketanji Brown Jackson's historic ascension to the Supreme Court -- and major pieces of legislation like the infrastructure law and CHIPS and Science Act.

"Two hard years. So much to be done. But so much progress," Klain tweeted.

Klain's departure is the one of the most significant exits for the White House so far, and comes as Biden is expected to soon announce whether he will run for a second term.

Klain previously said he expected Biden to announce his 2024 plans after the holidays.

"I'm just going to repeat what the president has said publicly," Klain said during the Wall Street Journal's CEO Council Summit in December. "That it's his intention to run. He's going to talk to his family and make a decision about that. I hear from a lot of Democrats across the country that they want him to run. And-- but the president will make that decision. I expect it shortly after the holidays. But I expect the decision will be to do it."

-ABC News Alexandra Hutzler contributed to this report.