Mercy Sr. Mary Killeen from Ireland stands behind Benjamin Alenga Luvai, a former street boy and chairman of the Gap Centre for street boys in Nairobi, Kenya in this 2001 photo. (CNS/Declan Walsh)
In the heart of Nairobi's Mukuru slum, where corrugated iron shacks gleam under the equatorial sun, Sr. Mary Killeen has woven a legacy of hope.
Known as the "Mother Teresa of Nairobi," this Dublin-born Sister of Mercy has spent nearly five decades transforming lives in one of Kenya's most impoverished corners. Her story is a tapestry of faith, grit and relentless service — a testament to the power of small acts done with great love.
Killeen, 79, was a young teacher in Ireland when a twist of fate called her to Kenya. In 1976, at age 30, she was sent to replace a sick colleague at Our Lady of Mercy Primary School in Nairobi.
"I did not choose to work in Kenya," she recalled in a 2018 interview with Global Sisters Report. "Another sister got sick and I was asked to replace her and I was not happy as such, because I was happy where I was working in Ireland."
What began as a temporary assignment became a lifelong mission when she encountered the sprawling Mukuru slum, just a stone's throw from her school, where 600,000 people live in grinding poverty.
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Her life mirrors the ethos of Mother Teresa, whose own work in Kolkata's slums inspired the nickname bestowed upon Killeen. Like Teresa, Killeen's faith is her compass. "God still loves the world," Mother Teresa once said, "and He sends you and me to be His love and His compassion to the poor." In Mukuru, Killeen embodies this call, her white habit a beacon amid the slum's vibrant chaos.
From a corrugated hut to a network of hope, Killeen's journey as the "Mother Teresa of Nairobi" is a vivid reminder that one person's compassion can ignite change. Her story, etched in the lives of thousands of children now educated, skilled and dignified, proves that even in the darkest corners, love can build a brighter world.
Mukuru, with its trash-strewn streets and shanties cobbled from cardboard and tin, was a world apart from the orderly classrooms of her private Catholic school. Yet the sight of children roaming without education stirred something deep within her. "One time, I visited Kayaba, one of the villages in the slum, and saw there were hundreds if not thousands of children out of school. I wanted to do something," she reminisced.
By the 1980s, nearly half of Nairobi's children lacked access to education — a crisis magnified in the slums. Killeen said she couldn't stand idly by.
"I went to my superior and the people of the slums, and I also went to the church and the government for support," she added.
In 1984, her superiors gave her the green light to work full time in Mukuru. She approached the community with a bold proposition:
"Build me a hut, and I will teach your children," she said.
The residents, with support from Nairobi's City Council, erected a simple corrugated structure. Alongside Fr. Manuel Gordejuila, Killeen launched the Mukuru Promotion Centre in 1985 — a seed that would grow into a network of schools, clinics and skills training programs serving more than 170,000 people. Today, the centre boasts four primary schools educating 5,600 pupils, along with programs teaching masonry, carpentry, plumbing, dressmaking, catering and vegetable growing. Over her lifetime, Killeen has helped an estimated 11,000 children.
Killeen's approach was inclusive, welcoming people from all religions into her schools and services, reflecting her belief that "collaboration and goodwill in any form is encouraged." Her health initiatives tackled HIV/AIDS, malnutrition and maternal care, with a Voluntary Counseling and Testing Centre established in 2004 and a clinic staffed by professionals from St. Elizabeth School of Community Health in Slovakia.
Her work caught global attention. In 2015, Pope Francis met Killeen in Nairobi's Kangemi slum, where she delivered a five-minute presentation before he announced funding for a Mukuru Promotion Centre project.
"Your visit gives us courage," she told the then-pope. "By coming here, you shine a light on the challenges. Your meeting with us gives us dignity."
Two years later, Austrian State Television aired a 50-minute documentary, "Sr. Mary of Nairobi," with producer Gernot Lercher calling her "the Mother of Mukuru" for her fearless fight against corruption and poverty.
In 2018, Ireland honored Killeen with the Presidential Distinguished Service Award, presented by President Michael D. Higgins at Áras an Uachtaráin. The award recognized her 42 years of "outstanding development and humanitarian work" in Nairobi's poorest areas. Trnava University in Slovakia also conferred an honorary doctorate in 1997 for her contributions to Mukuru.
Mercy Sr. Mary Killeen greets a child in the South B slums in Nairobi, Kenya in this 2001 photo. (CNS/Declan Walsh)
Despite all the attention, Killeen remains grounded.
"The word 'impossible' doesn't exist in her vocabulary," Lercher noted, a sentiment echoed by those who've seen her navigate Nairobi's challenges with unwavering resolve.
Although elderly, Killeen continues her work despite funding shortfalls for the Mukuru Promotion Centre. She invites donations to sustain the mission — a reminder of the ongoing need in Mukuru.
I would say, as sisters, we should concentrate on the very poor. You know, in Kenya, it is a shame because sisters need the money to survive so they opt for private schools where people can pay," she said. "But that type of work is not as fulfilling as working with the people who have no chance and who cannot pay. I think it is good, as religious, to work with the very poor as much as possible for it gives meaning to our lives."
John Slattery, who serves as chairman of Africa Direct which has partnered with Killeen in the past, told The Nation this past March: "Walking through the extensive Mukuru slums with her is akin to accompanying a football star. She is well known and popular with everyone."
This story was originally published at Religion Unplugged.
