[1] He was known for his work for DC Comics on their Legion of Super-Heroes and Justice League titles as well as for being the co-creator of Lobo, Rocket Raccoon, and Jaime Reyes.

[2][3] His first published work was "The Sword and The Star", a black-and-white text story featured in Marvel Preview #4 (Jan. 1976), with writer Bill Mantlo.

[8] After successfully experimenting with his unorthodox brand of humor in the 1985 Legion of Substitute Heroes Special, Giffen began employing this style in many of his works.

[10] The success of that series led to a spinoff in 1989 titled Justice League Europe also co-written with DeMatteis, and later with Gerard Jones, and featuring art by Bart Sears.

Giffen created the alien mercenary character Lobo (with Roger Slifer)[14] as well as the irreverent "want-to-be" hero Ambush Bug.

[15] A Doctor Fate series of back-up stories, written by Martin Pasko and drawn by Giffen appeared in The Flash #306 (Feb. 1982) to #313 (Sept.

Giffen worked on titles owned by several different companies including Woodgod, All Star Comics, Drax the Destroyer, Heckler, Nick Fury's Howling Commandos, Reign of the Zodiac, Suicide Squad,[20] Trencher, T.H.U.N.D.E.R.

For Valiant Comics, Giffen wrote X-O Manowar, Magnus, Robot Fighter, Punx and the final issue of Solar, Man of the Atom.

Giffen took a break from the comic industry for several years, working on storyboards for television and film, including shows such as The Real Ghostbusters and Ed, Edd n Eddy.

Giffen was the breakdown artist on the DC Comics title 52, a weekly series following in the wake of the Infinite Crisis crossover, written by Geoff Johns, Greg Rucka, Mark Waid and Grant Morrison.

He was the lead writer for Marvel Comics's "Annihilation" event,[24] having written the one-shot prologue, the lead-in stories in Thanos[4] and Drax,[25] the Silver Surfer[26] as well as the main six issue mini-series.

After an early stint at Marvel, he began doing layouts for artist Wally Wood during the 1976 revival of the Justice Society of America in All Star Comics.

He peppered his artwork with in-jokes such as upside down Superman logos, hidden Marvel characters, eyeball creatures, and scrawled humorous messages on signs in the background of his panels in the alternate futuristic alphabet Interlac.

Soon thereafter he developed a scratchier, more impressionistic style, using a highly stylized method of drawing directly with ink, on titles such as Trencher, Lobo Infanticide and Images Of Shadowhawk.

He relied on others such as Robert Loren Fleming and Tom and Mary Bierbaum to supply captions and dialogue, even when he was the main creative force behind the book.

During his late 1980s-early 1990s run on the Legion of Super-Heroes, light comical issues were often followed by darker ones where popular characters were maimed or killed.

[43][44] On February 7, 2009, it was announced at the New York Comic Con that he would spearhead a revival of Doom Patrol, a title which he had long said he wanted to write.

The article pointed out that Giffen had changed from a slick, clean Jim Starlin-esque style to an avant-garde, heavily inked one.

[48][49][50] The Comics Journal returned to the subject two years later, accusing Giffen of swiping from Muñoz again in a 1988 story drawn by him for the anthology Taboo.

Giffen acknowledged Muñoz's influence, and in 2000 referred to the controversy this way: I had a bad incident with studying somebody's work very closely at one point, and I resolved never, ever to do it again.