[3] Lopez began his lettering career as a freelancer for Marvel Comics in 1986, rapidly rising to prominence for his speed and creativity.
[3] From 1989 to 1996, Lopez was the regular letterer on a number of Marvel titles, including Marc Spector: Moon Knight, The Punisher, Guardians of the Galaxy, Deathlok, and X-Men 2099.
In 1992–1994, Lopez lettered for a number of Valiant Comics titles, including Magnus, Robot Fighter and almost the entire run of X-O Manowar.
Lopez has designed logos for such titles (among others) as Marvel's Wally the Wizard (1985),[4] Iron Man (1985), Classic X-Men (1986), Comet Man (1987),[4] Excalibur (1988), and Spider-Man 2099 (1992); and DC's Green Lantern (1994 and revised in 2002), Green Lantern Corps (2006), and Justice League of America (2006).
[5] In addition, as DC's cover editor, Lopez solicits new logos from freelancers, and modifies existing designs.