WILMINGTON, Del. — President-elect Joe Biden's decision to fill his White House and Cabinet with longtime colleagues has led to frustration from liberals, civil rights leaders and younger activists, who worry he's relegating racial minorities to lower-status jobs while leaning on Obama-era appointees for key positions.

Biden’s Cabinet process has also discomforted some allies on the Hill, who say senators from his own party have not been sufficiently consulted about picks, even though Biden will need influential Senate Democrats to help steer nominees through the confirmation gauntlet. Senior Democratic senators have gotten little or no advance warning about the president-elect’s selections, according to a half-dozen senior congressional officials and others familiar with the process.

Taken together, these concerns bring into focus the challenges Biden confronts as he tries to unite the party around his ambitious agenda and immediately staff his administration. Dissatisfaction from the party’s grass roots, and lawmakers not made aware of the president-elect’s decisions, could hobble Biden’s ability to quickly move his nominees into position so he can execute on pressing priorities like the coronavirus pandemic response.

On the campaign trail, Biden promised to appoint a Cabinet that elevated up-and-coming leaders in the party and reflected the diversity of America.

Of the 14 Cabinet-level picks announced so far, seven are women, and nine are people of color. But Biden has also mostly selected people he’s known for years, or even decades. The average age of Biden’s department heads so far is 63, according to a Washington Post analysis. About 80 percent of the White House and agency officials he’s announced have the word “Obama” on their résumé from previous White House or Obama campaign jobs, the analysis found.

Some of them will be in roles similar to the ones they held in the last Democratic administration.

Tom Vilsack — secretary of agriculture for all eight years of President Barack Obama’s term — will take up that role again under Biden, if confirmed. Vivek H. Murthy, who was Obama’s surgeon general, would have the same job for Biden. The incoming White House chief of staff, Ron Klain, worked for Biden in the same capacity when he was vice president.

“We cannot move forward in a new direction with just the same people including some of the people who are responsible for the mess we are in,” said Evan Weber, the political director of the Sunrise Movement, a liberal group focused on climate issues. “We would like to see more young progressives in roles in the Biden administration.”

Weber and other liberals say they do not believe that Obama, who came into office with his party in control of both chambers of Congress, took bold enough steps on issues from climate to banking rules.

And while Biden’s team is racially diverse, some observers note that the president-elect is leaning on older Black and Hispanic leaders, who may not understand the needs and priorities of a younger generation.

“There’s more appointments of color, but there is a lot of same old, same old,” said Sayu Bhojwani, a pro-immigration activist and president of New American Leaders, a group that pushes for more diversity among elected leaders. “Having voices of color who have kind of grown up in a system that wasn’t built for people of color means that we’re not going to get innovation and we’re going to get people who are risk averse because they know the system.”

Biden’s bias toward government veterans stems from his view that the Trump administration steered the country significantly off track, that deep expertise will be necessary to restore it and that there’s not time for a learning curve, according to transition aides who spoke on the condition of anonymity to discuss internal deliberation.

And the focus on Obama-era appointees could have advantages, some argue, creating in Biden’s team an automatic cohesiveness. “This is the mother-of-all-alumni group,” said Reed Hundt, who worked on the Obama transition and is author of the book “A Crisis Wasted” about decisions made during that time to respond to the Great Recession.

In contrast, he noted, many members of Obama’s economic team didn’t know one another or the then-president particularly well when they started. That left key players learning to work together and determining how to best work with the president as they were also trying to solve a huge economic crisis.

Biden’s engagement with the Hill has also worried some allies, who say the lack of consultation has often caught top senators off guard and, with one prominent pick, left them scrambling to get on the same page with an administration nominee. The lack of notice, in particular, to the ranking Democrats on committees was notable because that senator is poised to be the nominee’s chief defender during the confirmation fight against attacks from Republicans.

For instance, the transition team never reached out to Sen. Bernie Sanders (I-Vt.) about Biden’s decision to tap Neera Tanden as director of the Office of Management and Budget, according to a person familiar with the lack of communication, despite Sanders’s role as the top Democrat on one of the committees that will hold Tanden’s confirmation hearings. Sanders’s office declined to comment.

And while Sen. Jack Reed (D-R.I.), who in 2017 was adamant that he would never again support waiving a law meant to uphold civilian leadership at the Pentagon, was told about Biden’s decision to tap recently retired Gen. Lloyd Austin as defense secretary, one person said the discussion was rather perfunctory — a surprise, considering Reed’s definitive remarks nearly four years ago.

Biden’s decision left Reed, the Democrats’ point person on defense issues, in an uncomfortable position as he tried to reconcile his past statements on the waiver and the fact that the president-elect’s pick as defense secretary would need one, turning a policy meant to be a once-in-a-generation exception into a pattern of installing recently retired military leaders at the Pentagon.

A transition official said Biden’s team, on top of consultation with lawmakers, tries to notify lawmakers ahead of Cabinet announcements and brief their offices within a few hours of the news being public. Senior congressional aides also said that while they believed Biden could do a better job of reaching out to Democratic senators, they recognized transition officials were in somewhat of a bind because the Senate majority remains up in the air.

Many GOP senators won’t even acknowledge Biden is the president-elect.

Aides also said the transition’s consultations and notifications were limited because Biden’s team appeared concerned about leaks, with one congressional official saying that, “certainly, they keep things appropriately close to the vest” when it comes to Biden’s decisions on nominations.

Incoming White House press secretary Jen Psaki defended the process Friday, saying there have been “hundreds of engagements” between transition officials and congressional staff members as part of the confirmation process.

Before he chose Janet L. Yellen to be his treasury secretary, for example, Biden’s team sought input from Sen. Elizabeth Warren’s top allies, a delicate process given that the Massachusetts Democrat and one of Biden’s opponents in the presidential primaries was hoping that she’d be the one selected for the role.

Sen. Mark R. Warner (Va.), the top Democrat on the Intelligence Committee, weighed in with transition officials on his views about who should be tapped as director of national intelligence, according to a spokeswoman — a slot that ultimately went to Avril Haines.

A spokesman for Sen. Debbie Stabenow (Mich.), the top Democrat on the Agriculture Committee, said she was notified in advance of the announcement that Biden planned to ask Vilsack to reprise his role.

“President-elect Biden’s team has been incredibly responsive and stayed in close contact about the process and my priorities,” said Sen. Ron Wyden (Ore.), the top Democrat on the influential Finance Committee, which manages confirmations for top Cabinet positions overseeing health care, fiscal policy and trade. “Biden is picking his team. I didn’t expect to be asked for explicit sign off.”