Gordon Brown has taken up a role with the UN as the body's special envoy for global education, he said in a statement on Friday evening.
The former prime minister said it was a "great privilege to be appointed UN Special Envoy for Global Education and work with Ban Ki-moon to achieve quality education for all."
"He will focus on countries with the highest burden of children out of school, recognizing that nearly half of out of school children are in countries affected by conflict. He will help bring about change, mobilize resources and generate additional and sufficient funding."
The role comes in the same week another former Labour prime minister, Tony Blair, took up a formal post as an adviser to the party on sports policy.
Brown said: "My hope is that the Secretary-General’s ‘Education First’ initiative will accelerate progress not only towards the Millennium Development Goal on education, but across all the goals."
Brown, who blogs for The Huffington Post, has previously condemned the international community for failing to protect the rights of children in countries ravaged by war to an education, calling the effects "devastating".
In January, Brown called for the creation of a worldwide fund to combat what he describes as the "hidden and silent emergency in education". At the time, he claimed progress towards the United Nations' goal of universal primary education by 2015 had stalled and urged the developed world to reignite the drive to provide education worldwide.