They wanted more than you’d find in a typical Sunday collection plate.

Officials from the National Museum of African American History and Culture approached the leaders of the historic Alfred Street Baptist Church in Alexandria with a surprising request: Would the African American congregation pledge $1 million to become a founding donor to the $540 million museum, opening Sept. 24 next to the Washington Monument on the Mall?

The gift would be historic, museum officials said, representing the largest donation by a faith-based organization. It would be groundbreaking for the congregation, too, which had never given that much to another institution.

Pastor Howard-John Wesley met with the church’s leaders, and they agreed to ask the congregation for support and to make up the difference from the church’s reserves. The church’s members gave a standing ovation the November day the check was presented to Lonnie Bunch, the museum’s founding director, Wesley said.

“This is a proud moment for us, and praise be to God we had the resources,” Wesley said. “Black stories matter [and] there’s a need for claiming and proclaiming our own history and heritage.”

The Rev. Howard-John Wesley, pastor of the Alfred Street Baptist Church in Alexandria, which donated $1 million to the National Museum of African American History and Culture. (Dayna Smith/for The Washington Post)

The request highlights the bold thinking of the museum’s fundraisers, who tapped into Alfred Street’s tradition of service and its pride in its 200-year history in making their appeal. Such creativity has been a successful hallmark from the start. Private donors — including Shonda Rhimes, the TV producer behind “Scandal” who pledged $10 million — have contributed $245 million to the capital campaign. Combine that with $270 million from the federal government, and the museum is $25 million shy of its $540 million goal.

[A first look inside the Smithsonian’s African American Museum: Stunning views, grand scale]

The museum has received donations for other purposes, too, including education and endowment. In all, private contributions total $265 million.

“This is a staggering amount of generosity,” said Emmett Carson, president and chief executive of the Silicon Valley Community Foundation and an authority on African American giving. “It’s a symbol that black . . . philanthropy is not an oxymoron.”

Since 2006, museum officials have sought out the usual suspects, including national foundations and corporations and stalwart Smithsonian donors, who are predominantly white. But they also appealed to wealthy African Americans and their corporate, civic and religious institutions. They discovered families who weren’t on commonly shared donor lists and asked for bigger gifts from those with a history of philanthropy.

The diversity of the supporters is also remarkable. African Americans represent 74 percent of the individuals who each gave $1 million or more, officials said, a figure almost double their early expectations. And African American organizations represent 28 percent of institutional support for the museum, including black sororities, fraternities and civic groups.

Museum officials wisely capitalized on the election of President Obama, Carson added, noting that Obama’s influence cannot be overestimated. “They took advantage of having the first African American president, and of President Obama’s legacy,” he said. “It is almost unbelievable that in 200 years we have gone from being chattel to having someone occupy the Oval Office.”

‘I want this for my children’

Bunch said the campaign sought diversity in its supporters, just as it does in its staff and volunteers. “I have the most diverse staff of any museum in America, and we have a diverse council,” he said. “If this is the quintessential American story, I want all Americans to help shape it.”

The list of founding donors suggests they were successful. Among them are the Ford, Gates, Rockefeller and Mellon foundations, General Electric and Walmart, Oprah Winfrey and Samuel L. Jackson, the NBA and the NFL, Carlyle Group co-founder and philanthropist David M. Rubenstein and former secretary of state Colin L. Powell. The 17 largest gifts account for at least $140 million, according to the museum’s donor recognition list. That’s more than half of the campaign goal.

It is typical of capital campaigns that a small group of donors gives a majority of the money, said Tim Seiler, a fellow at the Lilly Family School of Philanthropy at Indiana University-Perdue University Indianapolis. Usually, the largest 10 to 15 gifts represent 60 percent of the total, he said.

Earl W. Stafford and his wife, Amanda, who are members of the Alfred Street Baptist Church, also donated $2 million on their own.

“I want this for my children and grandchildren . . . for generations unborn who will better understand how we fit into this great American fabric,” said Earl Stafford, a Northern Virginia philanthropist and entrepreneur. “This is going to have far-reaching importance not only in the African American community, but in all of America.”

[Finish line in sight, African American museum seeks money, objects]

The museum’s game plan mirrors the practices outlined in a 2015 study on philanthropy that examines how nonprofit groups can appeal to nonwhite donors in an increasingly diverse world. The report, “Diversity in Giving,” found that African Americans often do not contribute to campaigns because they haven’t been asked for support. Compared with the larger donor universe, African American donors are more likely to contribute to efforts that support their heritage and community, to prefer opportunities that have a social component and to value diversity within the organization.

The museum hit all these marks. Mark Rovner, chief executive of Sea Change Strategies of Takoma Park and the author of the report, said the NMAAHC is a “living example” of the study’s findings. “Philanthropy tends to be dominated by white America,” Rovner said. “Obviously, there’s so much cultural pride in that museum, and it is so overdue. I can’t imagine a better charitable [opportunity], especially for wealthy African Americans.”

There were some challenges, especially in the early years. Federal funds didn’t always come though when expected. In 2012 and 2013, at the start of construction, federal appropriations were $64 million less than the Smithsonian’s request, according to an audit by the Smithsonian inspector general. Fundraisers missed their annual goals four times in the first seven years (2006 to 2012), the 2013 audit showed. (The Great Recession played a role in at least two of those years, officials said.) One year after breaking ground, the museum had received only $304 million, according to the inspector general.

To keep the work on schedule, the Smithsonian borrowed $100 million over 10 years, at a cost of $18.5 million in interest. (Smithsonian officials said most of these funds were used for the African American museum, but some went to renovation projects at the Renwick Gallery and National Museum of American History.)

Construction issues and design changes also caused the opening to be delayed a year and increased the cost of the project by $40 million, to $540 million.

[Even a $540 million museum can suffer from cost cutting]

‘A gift from the soul’

For many of the thousands of donors, the gifts are personal. T.B. Boyd III is the fourth generation to lead a family publishing company in Nashville that was founded by his great-grandfather, Richard Henry Boyd, a former slave. In addition to $1 million, he and his family have donated artifacts, including a printing press from the publishing business.

“It is patriotic, it’s a gift from the mind, a gift from the soul,” Boyd said. “If we don’t do it, who is going to?”

That attitude has prompted many small donors, too, including Carson, who believe they were making history by writing checks. The museum has more than 100,000 donors who have contributed as little as $25 a year to become members — a surprisingly large number for an institution that has yet to open and the most of any Smithsonian museum. Bunch said the membership roster reflects the effort’s grass-roots support and its national reach. In addition, he said, the sheer number of annual contributions helped him make a case in Congress.

“I know how many members we have in every congressional district,” Bunch said. “It was important to show average people owned this project.”

With four months until the opening, museum officials are optimistic about completing the capital campaign. Meanwhile, they have received $2 million each from founding donors Bank of America, Prudential, Target and Kaiser to support the opening celebration. There will be other projects down the line that will require private support, too.

“You don’t want to limp across the finish line, you want to sprint,” Bunch said. “When President Obama opens the building, it is the beginning of our journey, not the end.”