Carver Federal Savings, the nation’s largest bank founded and run by African-Americans, has staved off possible collapse by raising $55 million in fresh capital.

The investors include Goldman Sachs Group Inc. and Morgan Stanley, which have agreed to invest $15 million each, while Citigroup Inc. and Prudential Financial have agreed to put in $10 million, according to an announcement from Carver’s parent, Carver Bancorp. American Express and three other firms are investing smaller amounts. Chief Executive Deborah Wright, who has led the bank since 1999, will remain at her post.

“I haven’t had a day this good in some time,” said a relieved Ms. Wright, who added she was “terribly grateful” for the financial community’s vote of confidence in her bank. “We have a lot of hard work ahead.”

The Harlem-based bank was ordered by federal regulators earlier this year to raise additional cash as it staggered under a hefty load of delinquent real estate loans. Under Ms. Wright’s leadership, the bank had moved from its traditional business of lending to one- to- four-family homes and into larger commercial real estate projects. That strategy backfired when the real estate market hit the skids and mortgages for low-income borrowers dried up.

Earlier this year, 12.3% of the bank’s loan portfolio was more than 90 days delinquent. The industry average is 4.9%, according to Federal Deposit Insurance Corp. data. In addition, although $74 million of its loans were well overdue, Carver had just $21 million in reserves to cover loan losses.

In February, the U.S. Office of Thrift Supervision ordered Carver to raise additional capital by the end of April or face being seized and sold to another institution—or simply dissolved. The amount Carver raised exceeds the amount demanded by regulators, Ms. Wright said.

Last month, the bank named a new chief financial officer—its fourth in the past three years—and said it hired an recruiter to find a new president and chief operating officer who would oversee lending, retail, marketing and human resources. Ms. Wright said the new executive would allow her to devote the bulk of her time to drumming up new business, adding that Carver will soon step up its marketing.

The Harlem business community galvanized to help rescue Carver, a fixture of the city since 1948. Lloyd Williams, CEO of the Greater Harlem Chamber of Commerce, said a private breakfast was held in late April at Sylvia’s Restaurant in which Ms. Wright and senior Carver officials met with former state Comptroller Carl McCall, former city Comptroller Bill Thompson, U.S. Rep. Charles Rangel and other Harlem business and political leaders to discuss ways to turn around Carver.

“It is exciting, and the community is now stepping up to the plate,” Mr. Williams said shortly after that meeting, “because they have been asked to do so in a meaningful manner.”