Mark Sean O'Hare (born July 18, 1968) is an American cartoonist who created the comic strip Citizen Dog.
O'Hare is well known for his work on animated television shows as a writer and storyboard artist for Rocko's Modern Life, SpongeBob SquarePants, Dexter's Laboratory, The Powerpuff Girls, Hey Arnold!, The Angry Beavers, The Mighty B! and Chowder. He performed storyboard work on The Ren and Stimpy Show. Throughout the run of the series, O'Hare served as the creative director and supervising producer on Camp Lazlo. He's currently a storyboard artist at Illumination Entertainment.
Although accepted into the aeronautical engineering program at Purdue University, O'Hare shifted focus after his sophomore year to study graphic design, later getting acceptance into the character animation program at California Institute of the Arts.
While a student at Purdue University, he drew a strip called Art Gallery for the student newspaper, The Exponent. The comic ran from the autumn of 1987 to the spring of 1990.
O'Hare has been nominated four times for an Emmy from the Academy of Television Arts & Sciences and won his first Emmy in 2007 for "Outstanding Animated Program" on Camp Lazlo and his second in 2008.
- Jet Scream
- Keeping Up With the Bigheads (with Jeff 'Swampy' Marsh)
- Power Trip
- Cabin Fever (also story with Hillenburg, George Maestri, and Joe Murray)
- I Have No Son (with Doug Lawrence and Robert McNally-Scull)
- Pipe Dreams (also story with Hillenburg and Maestri)
- Boob Tubed
- Born to Spawn
- Junk Junkies
- Belch of Destiny
- The Emperor's New Joe (also story with Hillenburg and Maestri)
- Fish-N-Chumps (also story with Tim Hill and Hillenburg)
- Old Fogey Froggy
- Fortune Cookie (also story with Hill and Hillenburg)
- Wacky Delly (with Jeff 'Swampy' Marsh and Dan Povenmire)