The former crack house on Randall Street in the South Bronx, one of several drug dens targeted for protest by Alexie Torres-Fleming and her church group 15 years ago, is now cleaned up, with a manicured lawn and a “For Rent” sign in its window.

In the process of trying to clean up and develop this troubled neighborhood, an effort that has earned Mrs. Torres-Fleming a Jane Jacobs Medal for urban renewal from the Rockefeller Foundation, a “For Rent” sign in a house where drugs were once sold represents a small victory in a larger struggle.

“We prayed at these crack houses,” Mrs. Torres-Fleming said, recounting the episode in an interview.

The daughter of Puerto Rican immigrants, Mrs. Torres-Fleming, 43, founded the Youth Ministries for Peace and Justice in 1992 across the street from the housing projects in which she grew up.

“We walked to seven different crack houses in the neighborhood and prayed. And it was life-changing because it brought together my personal politics as well as my faith,” she said.

Mrs. Torres-Fleming is one of this year’s two recipients of the Jane Jacobs Medal, who will be announced today. The medals are awarded to individuals whose efforts and visions have contributed to the “vibrancy and variety” of New York City. Now in their second year, the medals and a $100,000 award commemorate the Rockefeller grant bestowed in 1950 on the urbanist and journalist Jane Jacobs.

The incident with the drug dealers may have been life-changing for Mrs. Torres-Fleming, but it was also life-threatening. In retaliation, several drug dealers torched the interior of her church and made death threats against its pastor, she said.

The South Bronx has undergone a series of visible demographic changes, Mrs. Torres-Fleming said, recalling the “white flight” of business owners in the late 1970s, urban blight, and then her own migration to Manhattan from the Bronx shortly thereafter.

“I lived in Midtown, and I had a comfortable existence, but I began to feel a disconnect from home,” she said.

Once her church was vandalized, Mrs. Torres-Fleming decided to return to the Bronx in 1992, a move that surprised her family.

“People in my family were shocked, because they were like, ‘You made it out.’ The idea of coming back represented defeat and failure, but I knew that there was nothing else I could do,” she said.

Since then her work has included directing youth outreach and arts programs, attracting economic development, and supervising environmental and fiscal education programs, among others.

In September, her largest development project to date, a park on the Bronx River at a site where an old concrete plant was abandoned more than a decade ago, will open. The $10 million project, funded by city, state, and federal funds, aims to clean up the riverfront and is part of her goal to promote more “green” initiatives in a neighborhood hemmed in by four major highways. The 10-acre park will provide residents with a dock, a beach, a reading area, gardens, and ultimately an amphitheater.

“Alexie exemplifies a 21st-century Jane Jacobs, in that she is a person of color and a woman working in the South Bronx, which is a neighborhood most people had given up on and left for dead but which is now experiencing this rebirth,” the vice president of foundation initiatives at the Rockefeller Foundation, Darren Walker, said. “Jane Jacobs stood up to powerful forces like Robert Moses, and Alexie has stood up to drug dealers, gangs, and to powerful developers.”

Mrs. Torres-Fleming’s district in the South Bronx remains the poorest congressional district in America, and crime surged in the first quarter of this year. Murders spiked by 43%, with 30 homicides compared with 21 during the same period last year. Drugs are still a serious problem.

But Mrs. Torres-Fleming believes that it is just a matter of time before gentrification spreads to the South Bronx, which she says could push out long-term residents.

“When we became SoBro and Williamsburg became Billburg, the writing is on the wall in terms of what might happen to us as a community,” she said.

Asked to give the clearest and most obvious sign that her neighborhood may be facing gentrification, Mrs. Torres-Fleming responded, with noticeable concern in her voice: “We now have a Starbucks.”