David Finkel, a Washington Post journalist whose immersive reporting has produced illuminating stories about the toll of war on American troops and the struggles of refugees around the world, has been named one of 23 MacArthur Fellows, the charitable foundation announced.

Finkel, 56, is among a typically eclectic group of recipients of the annual “genius awards” bestowed by the John D. and Catherine T. MacArthur Foundation for “creativity, originality, and potential to make important contributions in the future.” Recipients receive $500,000 each, paid in quarterly installments over five years.

The 14 men and nine women named this year include the novelist Junot Diaz (author of “The Brief Wondrous Life of Oscar Wao,” the 2008 Pulitzer Prize winner for fiction); marine ecologist Nancy Rabalais of Louisiana; Boston pediatric neurosurgeon Benjamin Warf; mathematician Maria Chudnovsky of Columbia University; neurobiologist Elissa Hallem of UCLA; and Benoit Rolland, a stringed-instrument bow maker in Boston.

The 2012 class also includes another Washington writer, Dinaw Mengestu, a Georgetown University graduate who is now a professor there. Mengestu, 34, is the author of two novels that explore the lives and memories of African immigrants. He has also reported on Africa for magazines such as Harper’s and Rolling Stone.

Finkel, a veteran Post reporter who is now the newspaper’s national enterprise editor, is the author of “The Good Soldiers,” an acclaimed 2009 book that followed a U.S. Army infantry battalion that went into Iraq as part of the American troop “surge” in 2007. He spent eight months embedded with the unit to produce the book along with articles for The Post.

“I’m happy, I’m flattered and I’m pretty surprised,” Finkel said. “It’s not something you ever expect.”

In fact, when the MacArthur selection committee called him early one morning to give him the news, Finkel said he thought it was a storm-window installer calling to say he’d be late for an appointment. He was so disbelieving that he declined to return a follow-up call to the committee. “I thought the whole thing was a hoax,” he said.

Finkel already is among the most decorated journalists in the nation. He won a Pulitzer Prize for explanatory journalism in 2006 for a three-part series in The Post that followed a U.S.-funded program to promote democracy in Yemen. He had been a Pulitzer finalist on three previous occasions for explanatory and feature writing.

His work is typically the product of months of grueling reporting from remote and harsh locales — Kosovo, Iraq, Yemen, Central and South America and parts of the United States.

“He has lived and breathed ‘for’ the story of the Iraq war for five years,” said Post reporter Anne Hull, a fellow Pulitzer Prize winner and multiple Pulitzer finalist. “That’s a long time to stay inside such a painful story. Year after year, he has buried himself in the reporting and writing, with a fury that goes beyond dedication. As a friend, you can tell the story is always with him and the toll it has taken on him.”

The MacArthur committee cited Finkel as a journalist who pushes “beyond the constraints and conventions of traditional news writing” to produce stories “that heighten the reality of military service and sacrifice in the public consciousness.” It added: “As newspapers continue to contract and move away from immersion-based, long-form reporting, Finkel remains committed to crafting sustained narratives with an uncommon candor that brings poorly understood events and ordeals” to public attention.

“They’re not just endorsing my work in particular but a type of journalism,” said Finkel, who is at work on a book that chronicles the postwar lives of some of those he profiled in “The Good Soldiers.” “I like to think this is an endorsement of long-form journalism, in which you stay long enough to tell the story.”

As for the monetary award, Finkel said, “I don’t know how it changes anything. I’m either singleminded or simple-minded — I’m paying attention to the book I’m writing. I have a story I want to keep telling.” He said he has no plans to leave the newspaper.

Finkel is the second journalist affiliated with The Post to receive a MacArthur. The first was Katherine Boo, a former staff writer, who was recognized for her work in 2002.

Mengestu was born in Ethi­o­pia but emigrated with his family to the United States at the age of 2. He grew up in Peoria and Forest Park, Ill., and graduated from Georgetown in 2000.

His first novel, “The Beautiful Things That Heaven Bears” (2007), was about a struggling Ethio­pian refu­gee who runs a grocery store in gentrifying Logan Circle in Washington. A New York Times review called it “a great African novel, a great Washington novel and a great American novel.”

His second, “How to Read the Air” (2010), is about a young Ethio­pian American man who retraces his parents’ travels after they came to the Midwest from Africa. His third book will be published next year.

The MacArthur committee said Mengestu’s work enhanced the “understanding of the little-explored world of the African diaspora in America in tales distilled from the experience of immigrants whose memories are seared by escape from violence in their homelands.”

Mengestu, who recently moved back to Washington with his family after five years in Paris, called the award “a remarkable surprise.” He said he intends to use the money to continue his writing and to help create “a new system of publishing” in Africa, with the intent of both expanding the translation of Western books and promoting indigenous writers.

Others cited by the Chicago-based foundation were Maurice Lim Miller, who runs an anti-poverty agency in Oakland, Ca.; Laura Poitras, a New York documentary filmmaker whose work has focused on the war on terrorism; Melody Swartz, a bioengineer in Switzerland who studies the cellular response to tumors; and Chris Thile, a 31-year-old mandolin virtuoso who has fused bluegrass music with other genres.