Fazle Hasan Abed, the founder of the Bangladesh Rural Advancement Committee (BRAC), one of the world's largest NGOs, has died in Dhaka aged 83, the charity said.
Abed passed away while undergoing treatment for a brain tumour, according to a BRAC statement released Friday.
"We will honour his legacy with the same resilience, dignity and humility that he has instilled in us," the statement said.
Abed trained as an accountant in London and quit his well-paid job with oil giant Shell when war broke out in Bangladesh in 1971.
Using the proceeds of the sale of his London flat, he founded BRAC after the bloody battle for independence ended the following year.
At first, BRAC helped millions of refugees who streamed back into the new country, and then it diversified into healthcare, micro-finance, agriculture and education.
"BRAC decided to look at poverty as a multi-dimensional syndrome: not just income poverty, but poverty in terms of healthcare, in terms of education, the things that keep poor people poor," he said in an interview in 2010.
The NGO's approach has been hailed as one factor behind the drop in the proportion of Bangladeshis living in extreme poverty from 80 percent to around 40 percent of the population.
The approach proved so successful that BRAC, which has more than 100,000 local employees worldwide expanded into Africa -- including southern Sudan -- and has been lauded by world figures such as former US president Bill Clinton.
BRAC's overseas expansion began in 2001 when Abed followed the collapse of the Taliban regime and was struck by the parallels with Bangladesh in the early 1970s.
In recent years BRAC has also worked providing sanitation, health camps and child delivery centres to Rohingya refugees living in sprawling camps in Bangladesh.
The NGO helped nearly 150 million people out of poverty according to the World Food Prize, which honoured Abed as its Laureate in 2015.
Abed also received a knighthood from Britain in 2010 for his work.
A key element of BRAC's success in Afghanistan and other developing countries "is that we are from a developing country. We know and understand poverty," he told AFP after his knighthood was announced in Britain's New Year honours list.