(CN) — President-elect Joe Biden announced additions to his administration Tuesday morning as his transition team filled senior positions with veterans from his presidential campaign.

“America faces great challenges, and they bring diverse perspectives and a shared commitment to tackling these challenges and emerging on the other side a stronger, more united nation,” Biden said of his incoming team.

Mike Donilon, a campaign attorney and consultant, helped Biden craft his central message of running his campaign as a “battle for the soul of the nation” and played an integral role in writing many of Biden’s speeches. He will serve as a senior adviser to the president.

Steve Ricchetti, chairman of the Biden campaign and a veteran of both the Barack Obama and Bill Clinton White Houses, was tapped to serve as counselor to the president.

The two high-profile additions followed the announcement that Ronald Klain would serve as White House Chief of Staff and indicates Biden is intent on filling out the staff in the White House before moving on to his cabinet.

Biden named Jen O’Malley Dillon as his deputy chief of staff. O’Malley Dillon, who steered the Biden campaign through the primary season, is widely seen as one of the biggest reasons Biden triumphed over a crowded field of Democratic contenders after getting off to a slow start in Iowa and New Hampshire.

She joined the team in mid-March after jumping from the presidential campaign of Texas congressman Beto O’Rourke and became the first woman to lead a successful Democratic campaign for president. She is widely credited with turning Biden’s then-foundering campaign into a fundraising dynamo that would secure the nomination and win the White House.

Congressman Cedric Richmond, a Democrat from Louisiana, will resign his seat in the House to become a senior adviser in the Biden White House and run the Office of Public Engagement. Richmond formerly chaired the Congressional Black Caucus.

Biden will retain Dana Remus as counsel to the president. Remus clerked for both Samuel Alito and Antonin Scalia and was general counsel for the Obama Foundation. She served as the top attorney for the Biden-Harris campaign.

Biden also named Julie Chavez Rodriguez, another veteran of the Obama administration, as the director of the White House Office of Intergovernmental Affairs.

Rodriguez served as a top aide to Kamala Harris’s presidential campaign and then joined the Biden staff as a deputy campaign manager.

Annie Tomasini, Biden’s traveling chief of staff during the campaign, will assume the role of Oval Office Operations, filling out the president-elect’s White House staff.

“President-elect Biden and Vice President-elect Harris have an ambitious and urgent agenda for action,” said Klain, the incoming chief of staff. “The team we have already started to assemble will enable us to meet the challenges facing our country on day one.”

The president-elect also announced top positions for Jill Biden’s staff, including Anthony Bernal as top adviser and Julissa Reynoso Pantaleon as Jill Biden’s chief of staff. Pantaleon is a former deputy assistant secretary of state and served as an ambassador to Uruguay.

Most of the key members of the White House staff served on Biden’s campaign. Tomasini and Bernal were two of a handful of people to see Biden during large stretches of the campaign spent isolated at his home in Delaware due to the coronavirus pandemic.

Biden is expected to begin naming cabinet positions later this week.