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" ("comissario" is the Italian for "commissioner", "Basettoni" is a reference to O'Hara's sideburns), and in the Portuguese and Brazilian versions as "Coronel Cintra".
O'Hara plays a supportive role in Mickey Mouse's comic book mysteries as a police officer, who often relies on Mickey's help to catch villsins such as Pete, Phantom Blot and the like. Known fellow officers include his friend, Detective Casey.
In 1995 Italian authors Giorgio Pezzin and Romano Scarpa created the character of Petulia as O'Hara's wife.
O'Hara's first appearance in animation is in the animated TV series DuckTales. O'Hara made occasional appearances in various episodes of the series, including "Ducky Horror Picture Show" and "The Bride Wore Stripes".
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 that 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.
In Disney Speedstorm, Chief O'Hara appears as a Common Crew Member in the Mickey and Friends Collection. Added during Season 2: To Infinity and Beyond, O'Hara sports a black-and-white color scheme to match the two accompanying mid-season racers, Steamboat Mickey and Steamboat Pete. When equipped, O'Hara improves the racer's top speed and handling stats, and increases the power of the Shot skill. Chief O'Hara (as well as any other Crew Members introduced alongside Steamboat Mickey and Steamboat Pete) is currently only available through limited-time special events alongside the two Steamboat Willie characters.