After writing several short stories, a novella and book reviews, his debut crime novel Dead I Well May Be was published by Scribner in 2003. McKinty and his family moved to Melbourne, Australia, in 2008, to become a full-time writer. He also writes on and reviews literature for a number of publications including The Guardian.
McKinty is primarily known as a writer of genre fiction, crime and mystery novels and young adult fiction. Patrick Anderson of the Washington Post has praised McKinty as a leading light of the "new wave" of Irish crime novelists along with Ken Bruen, Declan Hughes and John Connolly.
 He often uses the classic noir tropes of revenge and betrayal to explore his characters' existential quest for meaning in a bleak but lyrically intense universe. Steve Dougherty writing in The Wall Street Journal praised McKinty's use of irony and humour as a counterpoint to the violent world inhabited by McKinty's Sean Duffy character. Some reviewers have criticised the explicit use of violence in his novels. However, in reviewing McKinty's Fifty Grand in The Guardian, John O'Connor called him a "master craftsman of violence and redemption, up there with the likes of Dennis Lehane."
Liam McIlvanney, writing in the Irish Times, singled out McKinty's lyrical prose style as the defining characteristic of his Sean Duffy series: "his prose is vital, vigorous and – as that other Carrickfergus boy, Louis MacNeice, would have it – 'incorrigibly plural'."
McKinty is a book critic and op-ed writer for The Guardian, The Sydney Morning Herald, The Washington Post, Literary Hub, The Australian, The Irish Times and Harpers. 
His debut young adult novel The Lighthouse Land was shortlisted for the 2008 Young Hoosier Award and the 2008 Beehive Award
The Dead Yard was selected by Publishers Weekly as one of the 12 Best Novels of 2006 and won the 2007 Audie Award for best thriller/suspense.
The Bloomsday Dead was long-listed for the 2009 World Book Day Award.
Fifty Grand won the 2010 Spinetingler Award for best novel and was longlisted for the 2011 Theakston Old Peculier Crime Novel of the Year Award.
Audible.com selected Falling Glass as the Best Mystery or Thriller of 2011.
The Cold Cold Ground won the 2013 Spinetingler Award for best crime novel, was shortlisted for The 2013 Prix Du Meilleur Polar, was shortlisted for the 2015 Prix SNCF Du Polar, and Crime Fest's 2013 Last Laugh Award.
I Hear the Sirens in the Street won the 2014 Barry Award for best mystery novel (paperback original), was shortlisted for best crime novel at the 2013 Ned Kelly Awards, was shortlisted for the 2014 Grand Prix de Littérature Policière, and for the 2014 Theakston Old Peculier Crime Novel of the year Award.
In the Morning I'll Be Gone won the 2014 Ned Kelly Award for best fiction, was shortlisted for the 2015 Audie Award For Best Thriller and was named as one of the 10 best crime novels of 2014 by the American Library Association.
Gun Street Girl was shortlisted for the 2016 Edgar Award (best pbk original), the 2015 Ned Kelly Award, the 2016 Anthony Award (best pbk original), the 2016 Audie Award for Best Mystery, was a Boston Globe "Best Book of 2015" and an Irish Times "Best Crime Novel of 2015."