White House Chief of Staff Ron Klain is planning to depart after the State of the Union address in February once his successor is firmly in place, according to an administration official.

Why it matters: Klain has been one of the most consequential chiefs of staff in the modern presidency and his departure will deprive President Biden of a trusted adviser who knows both ends of Pennsylvania Avenue.

• The New York Times first reported news of Klain's departure.
• The departure will come as Biden prepares to announce his re-election campaign and the White House is facing intense scrutiny from Congressional Republicans on classified documents found in Biden's former office at a Washington, D.C., think tank and his Wilmington, Delaware, home.
• Biden has tried to persuade Klain to stay and White House officials have privately suggested that he is irreplaceable.

Driving the news: Former COVID-19 czar Jeff Zients has been leading an outside review on how to organize Biden’s White House — and his cabinet — for the last two years of his first term.

• It looks less likely that there will be a big cabinet shake-up, especially after Biden and Treasury Secretary Jane Yellen decided that she will stay on.

What we are watching: Zients is among the candidates that could get the top job, according to people familiar with the matter.

• Other potential candidates include White House counselor Steve Ricchetti, who was considered for the top job at the beginning of the term.
• The White House could also bring in Tom Donilon, who served as President Obama’s national security adviser, and pair him with his brother, Mike Donilon, as co-chiefs-of-staff.
• Cathy Russell, Tom Donilon’s wife who is currently the executive director at UNICEF, might also be considered.
• Senior administration officials hold former New Orleans Mayor Mitch Landrieu in high esteem.
• Susan Rice, who chairs the Domestic Policy Council, now has experience in domestic and foreign policy.

Go deeper: Klain has been instrumental in the two projects that animated Biden's first two years in the White House: stocking the judicial branch with judges (and one Supreme Court Justice) and convincing Congress to spend billions on transportation, infrastructure and climate.

• Klain has also tended to the progressive wing in Biden's coalition, hosting lawmakers in the West Wing for meetings and visiting them on their own turf.
• Known for all-caps emails, fired off at all hours, Klain has confided in friends that he was exhausted from the job.

Editor's note: This story has been corrected to change Cathy Russell's job title.