[2] Youngblood was met with widespread critical acclaim, receiving positive reviews and features in The New York Times, The Washington Post, Esquire, The Wall Street Journal and Vogue, and others.

[6] In an early review, Publishers Weekly wrote that "This harrowing account of life in a besieged Ukraine reads like a bulletin from the front," and said that Daybreak echoed of both Hemingway and Casablanca.

Michiko Kakutani in The New York Times praised Gallagher for "his love of language, acquired as an avid reader, and his elastic voice as a writer – his ability to move effortlessly between the earnest and the irreverent, the thoughtful and the comic.

"[19] In The Wall Street Journal, Bing West wrote that "Understanding that comedy best captures the irony of the human condition, Mr. Gallagher pokes fun at himself, his soldiers and those above him ...

[25] Gallagher and Roy Scranton co-edited Fire and Forget: Short Stories from the Long War (Da Capo, 2013), an anthology of literary fiction by veterans of Iraq and Afghanistan.

Fire and Forget featured an introduction by National Book Award Winner Colum McCann, and stories by Colby Buzzell, David Abrams, Phil Klay, Siobhan Fallon, Gavin Kovite, Jacob Siegel, and others.

Be it Stephen Crane, E.L. Doctorow, Ernest Hemingway, Norman Mailer, Joseph Heller, Thomas Pynchon, James Jones or Tim O'Brien, war has been memorialized, glorified, satirized and revealed in all its valor and depredation ... Now, as another comes to a close, a new generation of authors will come forward to define themselves through their own fictional narratives.

"[37] And The Australian raved over the book, saying, ""Every so often a debut novel charges past the suburban stories tapped out in coffee shops and announces itself as a literary event.

Violent, intelligent, and beautiful, Youngblood is one of the best novels to come out of America's 21st-century wars, with an authority that eclipses most debuts and a literary talent that announces a commanding writer."'

"[41] Kirkus Reviews was far more positive, calling it "a keen extrapolation of a country launched down a radically altered historical continuum" and cited Gallagher's evolved and "elaborate" prose as a strength of the book.

[42] Marine veteran Peter Lucier of The Strategy Bridge called the novel "a triumph," and argued it shouldn't be read as war literature but as part of a "much broader canon of American and [anti-]imperial literature ... a stunning, short-paragraphed powerhouse that is both eminently readable as a thriller but can also bear the weight of a deep, close reading of the symbolism, rich with interpretative possibility and bold style choices.

"[43] In February 2022, as Russia's renewed invasion of Ukraine began, Gallagher joined fellow combat veterans Adrian Bonenberger and Benjamin Busch in the Ukrainian city of Lviv to voluntarily train a civilian defense force.

Longreads selected it as an editors' pick, describing it as "a reminder that in an age of geopolitical deceit and oil greed, there still exist people willing to take up arms in service of a democratic ideal.