American cartoonist (1917-1994). Born Jacob Kurtzberg in New York City, where he often drew large murals of space battles on the walls of nearby tenements. He started work as an animation in-betweener for cartoons like "Popeye" in the 1930s, then moved to syndicated newspaper comic strips and comic books. He teamed up with Joe Simon to create Captain America for Timely (now Marvel Comics) in 1940, then moved to National Periodicals (now DC Comics), where they worked on features like Manhunter, the Newsboy Legion, Boy Commandos, and the Sandman.
After marrying his wife Roz, he served in Europe during World War II. After the war, he and Simon worked together for another decade, creating comics like "Boys Ranch," "Young Romance," "The Fighting American," and "Black Magic" for a number of different publishers. He and Simon split their partnership in the mid-1950s, and Kirby worked on comics like "Challengers of the Unknown" and "Green Arrow" for DC, as well as the comic strip "Sky Masters."
Kirby spent most of the 1960s at Marvel, creating (with writer Stan Lee) some of the best-known comics of all time, including the Fantastic Four, the Hulk, Thor, the X-Men, and the Avengers. It is in tribute to this incredible period that Kirby is still referred to as "King Kirby."
In 1970, Kirby worked for DC as a writer/artist/editor, working on a number of projects, including Kamandi, the Demon, OMAC, and most notably, the New Gods (also known as the Fourth World), with characters like Orion, Darkseid, Mister Miracle, Metron, Granny Goodness, and many others.
In 1976, Kirby returned to Marvel projects, like Captain America, the Eternals, Black Panther, Machine Man, and Devil Dinosaur. He quit comics in the late-1970s to do more animation work, including the Fantastic Four cartoon and Thundarr the Barbarian. He returned to comics in the '80s, working on creator-owned projects and a few DC titles.
So what was it about Kirby that made him so influential? Before Kirby came along, comic art was mainly flat, uninspiring work, with the reader's point-of-view set up as if he were watching the action on a TV or movie screen. Kirby's art involved the reader more directly in the action -- instead of watching Captain America throw a punch, the POV and "camera" angle put you right there, as if Cap were slamming his fist right into your face. You weren't watching the Hulk menace a group of soldiers -- you were there, listening to this giant green monster bellow, feeling the impact on the ground as the goliath leaped into the fray. Even static shots were rendered more dynamically through more dramatic points-of-view and artistic angles (especially low angles that made the characters look even more heroic/powerful). And Kirby drew a lot of comics, many of them very popular, so people probably saw more Kirby comics than anyone else's during the Golden and Silver Ages. Some people think Kirby's art was a bit primitive, but there is not a single comic book creator today -- artist or writer -- who has escaped Kirby's influence.
His later years were marred by controversy, when Marvel refused to return his original artwork (if I remember correctly, he hoped to sell some of his original art to supplement his low retirement income), claiming that, since Kirby worked for Marvel on a work-for-hire basis, Marvel owned all of Kirby's artwork. Marvel's mistreatment of the man who had helped build the company became a big cause in the comics industry (and Marvel didn't help themselves any when they repeatedly (A) refused to back down when public opinion was against them and (B) acted like arrogant meanies during the whole controversy) and eventually, Marvel grudgingly returned Kirby's artwork.
Kirby's death in 1994 was met with sadness by the entire industry and even got some mention out in the "real world". Many fans consider him to be the best artist to ever work in comics, and even his detractors consider him to be one of the most influential comics creators ever.
Long live the King!