In March 1968, Gordon Parks published a portrait of an African-American child with disheveled clothes in Life magazine. His lips were swollen and cracked from eating plaster, in a futile attempt to ward off hunger. His eyes were plaintive and haunting.

Richard Fontenelle was too young to understand, but he and his family became the faces of urban poverty for millions of Americans. The photo essay Mr. Parks produced — “A Harlem Family,” which is now on exhibit at the Studio Museum in Harlem — changed Mr. Fontenelle’s life, and the lives of every member of his family, forever. It sparked in him a desire to succeed, and a lifelong friendship with Mr. Parks.

Three days after the show opened, Mr. Fontenelle died of heart attack. He was 48 years old.

Yet his was a life of triumph savored: Of the eight Fontenelle children who appeared in “A Harlem Family,” he was the only one who lived past his 30th birthday and built a stable family life. He gave much of the credit for his success to his mother and to Mr. Parks, who became a father figure to him.

“His whole life kind of centered around that event,” his widow, Michelle, said of his feelings about being in the groundbreaking photo essay. “I guess he took from that ‘What can I do with my life not to be like my brothers and sisters? What can I do with my life not to cause my mother this grief? What can I do with my life to make her life better?’”

Telling the Fontenelles’ story was a personal crusade for Mr. Parks. As he recalled in his memoir “To Smile in Autumn,” the assignment came at the end of the long, hot summer of 1967, a period of urban uprisings in black America. His editors asked him — the only African-American photographer on the magazine’s staff — to explain to them and to Life’s readers why the nation’s inner cities were going up in flames.

To Mr. Parks, the answers were clear: racism and poverty. To bring these political and economic abstractions to life, he knew that he had to focus on the daily lives of a single, impoverished black family.

Gordon Parks, courtesy of The Gordon Parks Foundation

The “cold hawk of winter was over the ghetto,” Mr. Parks remembered, by the time he introduced himself to Norman and Bessie Fontenelle, Richard’s parents, and convinced them to allow him to tell their story. They were a family in deep distress. Norman had been laid off from his job and could not find steady work. He and his wife struggled to feed their eight children and to keep their fourth-floor Harlem apartment warm.

Mr. Parks left his camera at home during the first week that he spent with them. Instead, he got to know the family and allowed them to become comfortable with his presence in their cramped apartment. By the time he pulled out his camera, he said in the 2004 documentary film “Family Portrait,” “I was practically in the family … I was like Uncle Gordon.”

During the month that he spent with the Fontenelles, Mr. Parks took hundreds of photographs. The 25 that appeared in “A Harlem Family” were spread over 16 pages, printed in gritty black and white. They seemed to claim the authority of documentary truth, yet their dark tones and shadows hinted at the subjectivity of Mr. Parks’s vision by refusing to reveal everything that he and his camera saw.

Gordon Parks, courtesy of The Gordon Parks Foundation

Bessie emerged as the story’s heroine, the gravitational force struggling to hold the family together. Mr. Parks described her sympathetically, writing in the magazine that she “appears to be a strong woman, especially in the early part of the day, when she looks younger than 39. As the day wears on, she seems to age with it. By nightfall she has crumbled into herself. ‘All this needing and wanting is about to drive me crazy,’ she said to me one evening.”

Another photograph early in the essay depicted her as the faltering sun around which the family orbited. She and four of her children were shown at the offices of the Poverty Board (Slide 1), with Bessie centered in the frame, facing the camera. Two of her children leaned on her shoulders, seeming to draw strength from her and, at the same time, to offer her support.

A young Richard dozed off in her lap.

Bessie and Richard also appeared in the essay’s final image (Slide 13). Few readers would have been prepared for it, despite the essay’s relentlessly grim tone. Published without a caption, it covered an entire two-page spread. In it, Bessie was seen lying on her bed, seemingly exhausted. One arm shielded her eyes, while Richard nestled under the other, staring directly into Mr. Parks’s lens. Norman had beaten her while in a drunken rage, leaving her neck scratched and swollen. She had thrown a pot of boiling water on him in retaliation, sending him to the hospital.

Gordon Parks, courtesy of The Gordon Parks Foundation

Those images jolted Life’s readers, whose response to “A Harlem Family” was immediate and overwhelming. Hundreds of letters poured into the magazine’s offices expressing sympathy and pledging money. Encouraged by the response, Mr. Parks urged Life to contribute enough additional money to buy and furnish a new home in Springfield Gardens, Queens, for the Fontenelles.

“Most important,” Mr. Parks wrote in “A Hungry Heart,” another memoir, “the magazine helped Norman get a job.”

But the Fontenelles’ new beginning came to a sudden end. A little over a year after the story was published, Life ran an editor’s note under the headline, “Tragedy in a House that Friends Built.” Late one night, the house had gone up in flames. Norman and his son Kenneth died in the fire; Bessie and the other children survived. The house and everything in it was destroyed. The family had only lived in the home for three months.

Bessie refused to allow Life to rebuild her new home; she wanted to move back to Harlem. The magazine, Mr. Parks wrote in “A Hungry Heart,” “found her a comfortable apartment and gave her money to get started again.”

Devastated by the episode, the family began what seemed to be an inevitable decline as AIDS and the streets claimed the lives of one child after another. Yet Richard escaped his siblings’ fate. His widow, Michelle, said that his success was because of his belief in himself, his mother’s support, and his enduring relationship with Mr. Parks.

“Richard lived beyond Fontenelle years,” Michelle said in her apartment, where she keeps a large self-portrait by Mr. Parks. “He was almost 50. He did so much beyond what he ever expected to do. No one would have expected to see him living now.”

At the time of his death, he had achieved middle-class success. The father of four children, he was married to his wife for 21 years. He had been employed by Columbia University for 23 years, having worked his way up from porter to maintenance supervisor. He composed music and ran a recording studio in his spare time.

Though he vowed never to be a statistic like his siblings — or the young victim seen in the Life photo essay — he remained proud to be a Fontenelle. “‘You know, my family was in Time-Life magazine,’” Michelle recalled him telling new friends. “Even through all the adversities and the negative sides to the story, it didn’t matter to him. It was just, ‘This is my family and this is how we lived and this is where we come from. But this is where we’re going and this is what I’m doing with my life now.’”

Bessie was overprotective of Richard, Michelle said. Small wonder, given how his siblings’ lives were destroyed by drugs, poverty and mental illness. He stuck close to her and grew up never abusing drugs or seeing the inside of a jail cell.

In “Family Portrait,” Mr. Parks mentioned that Bessie’s belief in Richard was a faith that mingled with worries about his safety. She once told him that if “anything happens to me, I hope you look in on him now and then,” he said.

He did. Over the years the two grew close. When Richard built a recording studio in the basement of the building where he lived and worked, Mr. Parks offered him advice on the music business. Later, he and Michelle would attend Mr. Parks’s exhibits. In Richard’s office, there is still a newspaper clipping from a 1997 New York Times article announcing a retrospective of Mr. Parks’s work at the Corcoran Gallery of Art in Washington. Accompanying the story is Mr. Parks’s famous photo of the Fontenelles at the welfare office.

“He loved Gordon to death,” Michelle said. “I kid you not. He couldn’t talk enough about Gordon. He couldn’t. He would always say, ‘I remember when Gordon and I would sit down and talk about…’ He would just call him. If he had a question about something or if he was just feeling a little bit down, he would give Gordon a call.”

This was especially true, Michelle said, after Bessie died in 1990. In some ways, Mr. Parks became the final — and most enduring — link to his family.

“I think it was comforting for him to know that there was still someone there,” Michelle said. “Through all of his family being gone and not having no one really to reach out to, on that side of the family, it was as if Gordon was that outlet for him.”

Yet a flesh and blood reminder of his past and future lives on. Among the four children that Richard is survived by is a son. His first name is Kenneth, for the brother who died in that house fire so many years ago in Queens.

His middle name is Gordon, for the man who changed everything.

And his last name is Fontenelle.

Gordon Parks, courtesy of The Gordon Parks Foundation

Reporting assistance provided by Kia Gregory.

“Gordon Parks: A Harlem Family 1967,” will be on view at the Studio Museum in Harlem through June 30. The catalog, “Gordon Parks: A Harlem Family, 1967,” is available from Steidl publishers.

John Edwin Mason teaches African history and the history of photography at the University of Virginia. Follow @johnedwinmason and @nytimesphoto on Twitter. Lens is also on Facebook.