The character was conceived by Floyd Gottfredson (and Merrill De Maris) for Disney as a stereotypical Irish cop. He first appeared in the newspaper strips in May 1939, in the serial "Mickey Mouse Outwits the Phantom Blot". In the German translations of the comics, he is known as "Kommissar Albert Hunter" (Kommissar means commissioner in German), in the Italian version as "Commissario Adamo Basettoni", and in the Brazilian version as "Coronel Cintra".
O'Hara would later go on to be a supporting character in Mickey Mouse Works. In Mouse Works, O'Hara would occasionally show up to arrest the villains Mickey has defeated, such as Pete after trying to steal Minnie's purse, Mortimer after it was revealed that the baseball belongs to Mickey (which Mortimer uses it to trick Mickey out of a dinner date with Minnie) and Minnie when she drove into Daisy's house as an attempt to give her a most famous apple pie that she just made. In Mickey Foils the Phantom Blot, O'Hara awarded Mickey, Donald and Goofy medals for saving the city from the blot.
O'Hara also made a special appearance on House of Mouse in the episode "House of Crime", where he visited the club to investigate the mysterious guest disappearances. It was soon revealed that the Phantom Blot was behind the thefts, and together Mickey and O'Hara defeated the villain. Later on he arrested Ludwig Von Drake for creating a cartoon that he said had him dying of laughter.
Other characters: Figaro | Mortimer Mouse | Clara Cluck | José Carioca | Panchito Pistoles | Humphrey the Bear | J. Audubon Woodlore | The Phantom Blot | Morty and Ferdie Fieldmouse | Chief O'Hara | Millie and Melody Mouse | Butch the Bulldog | Yen Sid | Magic Brooms | Willie the Giant | Beagle Boys | Oswald the Lucky Rabbit | Ortensia | Amelia Fieldmouse | Gus Goose | Salty | Launchpad McQuack | Webby Vanderquack | Cuckoo Loca | Roxanne | P.J. | Bobby Zimmeruski | Stacey | Grandma Duck | Gladstone Gander | April, May and June