A firm believer in experimentation and constant learning of new techniques, Miguel's first professional work for Marvel was the 8-issue miniseries Marvel Illustrated: The Iliad, written by Roy Thomas. That was followed by The Trojan War, also written by Thomas.
Later, Sepulveda penciled one of the Thor: God-Size Special stories, and collaborated in a couple issues of Secret Invasion: X-Men, before taking over as ongoing artist on Thunderbolts, first with Andy Diggle, and later with Jeff Parkeras writers. During that time, he also did a cover for Spider-Man: The Clone Saga #2 and the short story Wolverine: Carni-Brawl.
After finishing the cosmic event The Thanos Imperative, MIguel is now working on the epilogue to that series, the one-shot Devastation.
Moving to DC Comics, Miguel has worked on the Superman / Batman Annual, JLA #58, Green Lantern: War of the Green Lanterns: Aftermath, or the controversial Action Comics #900 story where Superman renounces his American citizenship.
After starting the New-52 Stormwatch book part of the New-52, Miguel moved to Red Lanterns with issue 10 of the book, and he's currently hard at work on the Wrath of the First Lantern crossover involving all the GL books!