WILL ALLEN already had the makings of an agricultural dream packed into two scruffy acres in one of Milwaukee’s most economically distressed neighborhoods.

His Growing Power organization has six greenhouses and eight hoophouses for greens, herbs and vegetables. There’s an advanced composting operation — a virtual worm farm — and a lab that is working on ways to turn food waste into fertilizer and methane gas for energy.

With a staff of about three dozen full-time workers and 2,000 residents pitching in as volunteers, his operation raises about $500,000 worth of fresh, affordable produce for one of what he calls the “food deserts” of American cities, where the only access to food is corner grocery stories filled with beer, cigarettes and processed foods.

Now, with a $500,000 “genius grant” that the John D. and Catherine T. MacArthur Foundation awarded him on Tuesday, Mr. Allen is dreaming bigger.

“I’d like to see Growing Power transform itself into a five-story vertical building being totally off the grid with renewable energy, where people can come and learn, so they can go back to their communities around the world and grow healthy food,” Mr. Allen, 59, said in an interview at the farm.

For Mr. Allen, only the second working farmer to win the award, according to the foundation’s records, his efforts are not meant simply to keep people well fed. He sees Growing Power as a way to organize people whose voices are rarely heard.

“I am a farmer first, and I love to grow food for people,” Mr. Allen said. “But it’s also about growing power. We grow relationships first; otherwise, nothing else makes sense.

“The movement I am part of is growing food and justice, and to make sure that everyone in the world has access to healthy food.”

This is a vision he has pursued for 16 years through the sales of produce and proceeds from grants. He has extended Growing Power’s operations throughout Milwaukee and Chicago, spreading the gospel of urban farming across the country and around the world and training fellow agricultural dreamers. Mr. Allen estimates that 10,000 people from around the world will visit Growing Power’s operations in the next year.

An imposing 6 feet 7 inches tall, Mr. Allen, who grew up on a farm outside Washington, D.C., played professional basketball for a time after college, mostly in Europe. In 1976, while working as a corporate marketing executive, he and his wife returned to her family’s farm south of Milwaukee.

He left a job with Procter & Gamble in 1993 and bought a roadside farm in Milwaukee’s economically depressed north side — the last remaining registered farm in the city — and got local teenagers involved in a gardening project.

Now, along with its main farm in Milwaukee, Growing Power, a nonprofit group, has a 40-acre farm in a nearby town, and school and community gardens throughout the city. The group also has operations in Chicago, including a garden at the Cabrini-Green housing project and urban farms in Grant and Jackson Parks.

In addition to retail sales at the Milwaukee headquarters, Growing Power sells to food co-ops, other retail stores and about 30 restaurants in the Milwaukee and Chicago areas.

Growing Powers’s headquarters looks like a farm stand in need of a paint job and top-to-bottom clean-up. Weeds grow through cracks in the surrounding sidewalk.

It has a strong aura of the 1960s community center. Young and old mill about, shopping and waiting for a tour or a training session or a conference.

Hand-written notes on bulletin boards list prices for fruits and vegetables (all greens 89 cents a pound; peaches, plums and nectarines $2.99 a pound).There is constant activity, with projects at various stages of completion. Mud-encrusted boots share greenhouse space with pick-axes and countless pots of salad greens.

“It’s a crazy place,” Mr. Allen said.

Mr. Allen also takes on what he calls “the racism in all aspects of our lives, whether it is food or medicine or politics.” Shortly before receiving his MacArthur award, for instance, Allen’s group sponsored a conference aimed at “dismantling racism and empowering low income and communities of color through sustainable and local agriculture.”

As with any top-notch farmer, Mr. Allen takes special care with his soil. Using millions of pounds of food waste, his farm produces endless compost piles, which are then enriched by thousands of pounds of worms, essential to producing what he calls the highest quality fertilizer in the world.

“There are worms in every pot of soil and every tray of vegetables in this greenhouse,” Mr. Allen said.

His food, free of chemicals and delivered fresh, tastes better, Mr. Allen said. “We beat the wholesalers with taste,” he said. “And that’s what the really good chefs understand.”

Paul Kahan, the chef and managing partner of the award-winning Chicago restaurants Blackbird and Avec, is one of the chefs who has been working with Mr. Allen’s organization. He first connected with Growing Power through a farmers’ market in Chicago about five years ago, and has done more and more business with them.

“They are wonderful people and do some interesting things that fit in with what we are trying to do,” Mr. Kahan said. “We buy regular produce, such as tomatoes, but they do some things in particular that we really love: pea tendrils, baby beet greens, nasturtiums, baby mustard greens.”

Mr. Kahan also underscored that Growing Power’s broader social goals in no way compromise the organization’s business and farming skills.

“Their quality is great,” he says. “And they are willing to drive stuff down in a pinch. They are very service-oriented.”

Mr. Allen said it all goes back to his family.

“My parents were farmers, and I am passing on what they did,” he said. “They understood all of this way back when, and now we’re having to go back to when people shared things and started taking care of each other. That’s the only way we will survive.”

“What better way,” he muses, “than to do it with food?”