All four new appointees previously worked under the Obama administration, many directly with Joe Biden.
The transition team named Carlos Elizondo as White House social secretary; Cathy Russell as director of the White House Office of Presidential Personnel; Louisa Terrell as director of the White House Office of Legislative Affairs; and Mala Adiga as Jill Biden's policy director.
"I'm proud to name additional members of our team who will help deliver the change America needs in these difficult times," Joe Biden said. "Their dedication to overcoming the challenges facing our country today are rooted in their diverse backgrounds and experiences. They will serve the American people and help build back better, creating a more just, equitable, and united nation."
Elizondo previously served as a special assistant to former President Barack Obama, and social secretary to the Bidens. As social secretary, he'll be responsible for coordinating official social events at the White House, including state dinners.
Russell is a member of the Biden-Harris transition team advisory board and was vice chairwoman of their campaign. She was ambassador for global women's issues during the Obama administration and served as Jill Biden's chief of staff.
As director of presidential personnel, her office will be responsible for overseeing and vetting the selection of presidential appointments.
Terrell oversees legislative affairs for the transition team and previously was assistant for legislative affairs for Obama and deputy chief of staff for Joe Biden when he was senator.
As director of legislative affairs, she'll work with senators and representatives to advance Joe Biden's agenda on Capitol Hill.
Adiga has served as a senior adviser to Jill Biden and senior policy adviser on the Biden campaign. She also worked as director for high education and military families at the Biden Foundation and in the State Department during the Obama administration.
As Jill Biden's policy director, she'll work directly with the future first lady to push her initiatives.
"To bring President-elect Biden and Vice President-elect Harris' agenda to life you must have a boundless team of experts ready for day one," incoming White House chief of staff Ron Klein said. "Today's appointees are respected leaders who will bring a commitment to serving the American people each and every day. They will support our work to build an administration and White House that represents America and delivers results."