Samuels grew up in Brooklyn, New York. In 1989, he graduated with a BA in history from Harvard College, where he was an editor of the Harvard Lampoon. Samuels became a Mellon Fellow in the Humanities at Princeton University, where he received a Master's Degree in history in 1993.
Samuels' first article to receive much public attention was a controversial 1991 cover story on rap music in The New Republic; the piece—which contended that the primary hip-hop audience consisted of white suburban teens—has been widely anthologized. A later article he wrote on rap music for The New Yorker was reprinted in the Best Music Writing of 2000 collection, edited by Peter Guralnick. His work has also been anthologized in Best American Political Writing of 2004, Best American Science and Nature Writing of 2006, and other collections., as well as the French nonfiction quarterly Feuilleton. 
Samuels has been a Contributing Editor at Harper's Magazine since 1996 and has written over a dozen long features for The New Yorker. Several of his stories have also been featured on the covers of The Atlantic and the New York Times Magazine. His work hearkens back to the New Journalism of the 1960s—a blend of first-person observation, detailed reporting, and a careful attention to language.
Samuels' pieces for Harper's are often panoramic takes on a single event, including the demolition of the Sands Hotel and Casino in Las Vegas, the riot at Woodstock 1999, a Donald Rumsfeld press conference at the Pentagon, and Super Bowl XL in Detroit. His features for The New Yorker and The Atlantic often focus on extreme subcultures and individuals with double identities.
His long profile of Yasir Arafat for The Atlantic in September 2005 was a finalist for the National Magazine Award in reporting, and was named one of the three most important articles of the year by the columnist David Brooks in The New York Times.
After publishing a controversial cover story in The Atlantic's April 2008 issue about the paparazzi who trail Britney Spears, Samuels appeared on NPR's On the Media, and offered an apology for having hurt the feelings of those subscribers who objected to finding Spears on the cover of the magazine. "Yes, I want to take full responsibility for destroying The Atlantic, 150-year-old pillar of American journalism," he said. "And now it's gone, thanks to me."
To open his long profile of the rapper Kanye West titled "American Mozart" in the May 2012 issue of The Atlantic, Samuels told of meeting President Barack Obama at a fundraiser at the Manhattan restaurant Daniel and asking him who he liked better – West or his Watch the Throne collaborator Jay-Z. Obama said that he preferred Jay-Z, but thought that West was "smart" and "very talented." When Samuels recalled that Obama had previously called West a "jackass," Obama replied "He is a jackass. But he's talented". An angry minority of Atlantic subscribers wrote to the magazine to express their bafflement at the comparison of West with Mozart.
In the April 12, 2010 issue of The New Yorker, Samuels published an account of his contacts with the Pink Panthers, a group of jewel thieves from Serbia and Montenegro who have reportedly stolen watches and jewels worth an estimated $250 million. The article, entitled "The Pink Panthers," was an idiosyncratic travelogue that detailed the group's cinematic robberies against the backdrop of recent Balkan history.
The style of the Panthers piece earned Samuels a rebuke from Pietry Calcaterra – the chief of Interpol's Pink Panthers unit – who wrote a letter of complaint to the New Yorker stating that "The victim is not the man wielding the gun, however colourful his alleged derring-do. The victim in an armed robbery is the person lying on a shop floor with a gun pointed at his head."
His immersive profile of White House speechwriter and deputy National Security advisor Ben Rhodes, published in the May 8, 2016 issue of the New York Times Magazine examined the use of traditional narrative techniques in the making and selling of American foreign policy in the age of social media. The article ignited a firestorm in the digital press, which was harshly criticized in the article by both Rhodes and Samuels, leading to an unusual response by Samuels to his critics in the pages of the Times titled "Through the Looking Glass With Ben Rhodes ."
In the spring of 2008, Samuels published Only Love Can Break Your Heart—a collection of his journalism—along with The Runner: A True Account of the Amazing Lies and Fantastical Adventures of the Ivy League Impostor James Hogue. The latter was based on his 2001 profile of the university confidence man James Hogue, in The New Yorker. In 2015, a French translation of "The Runner" was published under the title "Mentir A Perdre Haleine". 
In The New York Observer, critic Matt Haber called Samuels "a master of the new old journalism." In the same publication, critic Michael Washburn described Samuels' work in The Runner and Only Love as "thrilling"; "With an intelligence and unsparing lucidity reminiscent of Joan Didion, Mr. Samuels has written some of the best long-form literary journalism of the past decade." In a long review essay in The Nation, the critic John Palattella wrote that Samuels' achievement was "staggering" and compared his work favorably to that of Didion and Tom Wolfe: "Like Didion, Samuels investigates the vortex of American life, a feeling of weightlessness and existential drift that can swallow people whole, but he reports on it in an entirely different manner."
Reviewing The Runner for The New York Times, Keith Gessen wrote "Samuels is an elite narrative journalist, a master at teasing out the social and moral implications of the smallest small talk." Writing separately in the same publication about Only Love Can Break Your Heart, Jascha Hoffman described the collection as "a tribute to the twin American traditions of self-invention and self-deceit" and the author as "a brilliant reporter who has made a career of observing 'our national gift for self-delusion and for making ourselves up from scratch.'" In The Los Angeles Times, critic Richard Rayner cited the author's "wonderful feeling for the weirdness and truths of self-contained worlds"; he continued, "the writing is Joseph Mitchell-meets-Elmore Leonard, and a whole subculture comes to life. ... Samuels is heir to an American tradition."
James Hannaham wrote in The Village Voice that Samuels "has nearly autistic command of minor details and facts" and "achieves the glorious breadth and detail of a mural painter." Contrary to most critics, Hannahan preferred Samuels' book The Runner to his collected journalism in Only Love Can Break Your Heart, calling the book "terse, passionate and complicated," while criticizing Samuels' political writing for "a creepy lack of bias."Only Love Can Break Your Heart (2008)
The Runner: A True Account of the Amazing Lies and Fantastical Adventures of the Ivy League Impostor James Hogue (2008), ISBN 159558188X
The Best American Music Writing, 2000
The Best American Political Writing, 2004
The Best American Science and Nature Writing, 2006