When politicians of some renown leave public office, they often turn to special-interest lobbying and corporate advisory work. David Miliband took a different path.

A rising star in British politics, Mr. Miliband was just 29 when he became an adviser to Prime Minister Tony Blair. He then joined Parliament and held various cabinet positions under Mr. Blair and Prime Minister Gordon Brown. But in 2010, his party lost the general election, and Mr. Miliband fell short in the race to lead the Labour Party, narrowly losing to his brother, Ed.

In 2013, Mr. Miliband, now 53, accepted a job as president and chief executive of the International Rescue Committee, a nonprofit humanitarian group based in New York. The I.R.C. works in crisis zones around the world, delivering food, medical aid and education to people upended by conflict and disaster. Mr. Miliband is using the I.R.C.’s platform to call attention to the underlying causes of the crises his organization seeks to address, while also staying close to the field; next month, he will travel to Africa for an update on the group’s work fighting Ebola.

This interview, which was condensed and edited for clarity, was conducted at the I.R.C.’s office in New York.

I read that your father was a Marxist sociologist. Did that inform your views growing up?

My memory of my father is not that of a Marxist sociologist. It is of the dad who drove five kids in the back of a blue car to Saturday morning soccer in Leeds. Undoubtedly, I grew up in a political household. Both my parents were survivors of World War II, survivors of the Holocaust in a way, and I guess there were two things that are important that relate to your question in that respect. One is that politics are important, values are important. And second, you have to think for yourself.

What did your mum do?

She was a history teacher originally, who then became a stay-at-home mum. I think she would describe herself as a feminist; she was quite political as well.

So you were raised by a Marxist and a feminist. That’s quite a combination.

And probably a feminist who taught a Marxist that you couldn’t be a Marxist if you weren’t willing to be a feminist.

And your parents came to the U.K. as refugees?

My dad and his dad fled when the Germans invaded Belgium in 1940. My dad learned English and qualified for London School of Economics. My mom came to the U.K. at the age of 12 on her own in 1946, from Poland. Her father was killed in a concentration camp. There was a rabbi who brought children without parents to the U.K., and her mother sent her to start a new life as a child refugee.

What did you study in school?

I got interested in politics. I began to understand how British politics had come out the way it had. I was on the left, and we kept on losing. Why was that? And I sort of came to the conclusion that, if you can make a difference, you should. And if you don’t, it’s a waste.

You had several different roles in politics. What policy decision that you were involved in do you feel was most consequential?

I was involved in writing the manifesto for the ’97 general election. That was probably the most significant document I’ve ever been involved in writing. We had to ditch a load of bad policy and invent a load of good policy, which could both persuade voters and change the country. I think that governments actually have more impact over the medium term than they realize. We changed the country in quite fundamental ways. Socially, economically and in matters of peace and war in Northern Ireland. I honor people who are in politics, on whatever side. In my experience, the vast majority of M.P.s are not charlatans.

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