JACKSON, Miss. — When officials in Mississippi’s rural Holmes County, about an hour’s drive north of here, hired an architecture firm to fix the county’s ailing schools, they got back plans for a new $40 million high school to serve 1,200 students.

Holmes County is among the poorest counties in the nation, plagued by age-old systematic racism, with a population (18,340) that has been declining for more than a half-century. Holmes didn’t have $40 million to pay for a high school.

Community leaders reached out to Derrick Johnson, state president of the N.A.A.C.P., who also helps underserved Mississippi neighborhoods and districts with strategic planning. “Poor communities here are especially vulnerable,” Mr. Johnson told me the other day. “The whole system perpetuates exploitation. Residents need people they can trust.”

So Mr. Johnson enlisted Roy Decker and Anne Marie Duvall, husband-and-wife architects from Jackson.

Since they founded Duvall Decker nearly 20 years ago, the Deckers, as they’re known, have focused mostly on neglected corners in and around Jackson, Mississippi’s capital. To pay the bills, the two have redefined for themselves the ambit of a small architectural practice. They have become developers and even branched into building maintenance: a soup-to-nuts strategy that has allowed them more than just financial breathing room.

“Assuming more risk and responsibility has also given us a stronger voice, upfront, in this community, with politicians and businesspeople,” Ms. Duvall pointed out. “That’s because we have skin in the game.”

Architects are forever complaining about feeling undervalued, about having lost a seat at the decision-making table. Big ideas — the ones that shape whole cities and ultimately determine what is built, for whom and where — mostly happen “during the first 10 percent of any project,” as Mr. Decker likes to put it, meaning before architects are called in to design something. For the Deckers, like more and more socially minded architects today, reclaiming that seat is an increasing priority.

“When young architects apply to work for us,” Ms. Duvall said, “we ask what they want. Sometimes they say they want to design buildings that are unique, to express themselves. Other times they say they hope their work will have good consequences in a community. We’re finding more young people answering the second way.”

The architect Billie Tsien was a juror for the Architectural League in New York that just gave the Deckers an Emerging Voices award. “There’s a lot of fashionable work out there,” Ms. Tsien said. “Anyone who has done public work for nonprofits can appreciate the effort it takes to make even a smidgen of architecture happen.”

I met some of the people who live and work in the buildings the Deckers have designed. For Midtown, a Jackson neighborhood where the poverty rate hovers around 50 percent, the architects produced a master plan with affordable housing. The low-cost homes — wood-frame, three-bedroom modernist duplexes with…