In the early 2000s, Fernández was best known for providing the art for The Incredible Hulk, Wolverine and Spider-Man: Tangled Web series, as well as the "Operation: Crystal Ball" story arc of the Oni Press publication Queen & Country, written by Greg Rucka. In 2003, Queen & Country #8–12: "Operation: Crystal Ball" was nominated for the "Best Serialized Story" Eisner Award. The Publishers Weekly review of the Queen & Country: Volume 3: Operation: Crystal Balltrade paperback stated that "this book's pleasure lies in following the chase's twists and turns. Rucka and Fernandez accomplish this almost as well as any novel or film of the genre". Between 2005 and 2007, Fernández illustrated several nonconsecutive story arcs for the, written by Garth Ennis and then in 2008, he began illustrating the restarted '. In 2009 and 2010, Fernández illustrated "The Plague Widow" story arc of the Vertigo publication Northlanders, written by Brian Wood. In an interview on the series, Wood said "Leandro Fernandez, someone I've wanted to work with since seeing his work on Punisher MAX, is turning in perfect issue after perfect issue. All these books I write, with lots of details and a need for visual accuracy, are difficult for any artist to draw. He makes it look so easy". In 2011 and 2012, Fernández illustrated several nonconsecutive New Mutants story arcs, written by Dan Abnett and Andy Lanning and published by Marvel Comics. In 2014 and 2015, Fernández illustrated the nine-issue limited seriesThe Names, written by Peter Milligan and published by Vertigo. In an interview on the series, Milligan said "It's true that occasionally will try out a different way of doing something from how I've described it in the script. It's good when an intelligent and mindful artist does this, and it's even better when that artist is prepared to listen to feedback and maybe change things again. Leo's always been nothing but professional, and only wants the best for the book". Also in 2015, Fernández with Riccardo Burchielli illustrated ' #1, written by Mark Sexton, Nico Lathouris, George Miller and published by Vertigo. Jesse Schedeen, for IGN, wrote that "this issue features four different pencillers tackling different segments. These artists work together well in terms of achieving a unified visual tone. The problem is that the comic channels little of the film's frenetic energy or sense of style". The issue was in the top twenty of the "Apple iBooks US Bestseller List - Comics & Graphic Novels" for three weeks. In 2016, Fernández illustrated The Discipline, which was written by Peter Milligan and published by Image Comics. The Publishers Weekly review of The Discipline, Vol. 1: The Seduction trade paperback stated that "the artwork, both Fernández’s rendering and the colors by Cris Peter, are reminiscent of Hellboy and BPRD". In 2017, Fernández illustrated The Old Guard, which was written by Greg Rucka, colored by Daniela Miwa and published by Image Comics. In March 2017, Skydance Media picked up the rights to adapt the comic into a film. In 2018, Fernández began illustrating American Carnage, which was written by Bryan Hill and published by DC Vertigo as part of DC Entertainment's relaunch of Vertigo. Jim Dandy, for Den of Geek, wrote that "Fernandez’s art is stellar. The art feels a lot like Eduardo Risso’s on the surface, but there are some subtle differences that make it stand apart: the art in American Carnage is less blocky, which I think allows for a little more subtlety in expressions and body language". American Carnage ended with issue #9 in 2019 when DC Vertigo was shutdown. In December 2019, Fernández began illustrating the second volume of The Old Guard called The Old Guard: Force Multiplied.The Old Guard film was released on Netflix in July 2020.
