The man called Arty Sidesaddle was reportedly a writer who joined the criminal organization known as the Apparatus. He was bald with dark hair on the sides of his head, and he sometimes wore eyeglasses.
Arty Sidesaddle was one of three people associated with the Apparatus who disguised themselves and monitored activity at Diet Smith Industries as part of a scheme to steal valuable material and merchandise. He was identified by fingerprints that he and his associates left on cigarette packs that they discarded at their observation post.
Arty and his associates learned that Homer Barley (also known as "Peanutbutter") had aided the police in their attempts to identify them. They then arranged to abduct him. Homer was grabbed off the sidewalk and placed in a duffel bag in the backseat of a car that was then left on a railroad track. A train struck the car and demolished it. Homer was presumed killed.
The trio were then met by an unnamed fourth associate who picked them up in another car. Their car got a flat tire, and the criminals then stole the high-powered funny car belonging to the mechanic Girly Mac (who they encountered on the roadside). Mac warned them that they couldn't drive the funny car but Arty claimed to have been a stock car racer and believed that he could ably drive the vehicle.
The funny car was spotted by police in a Space Coupe and a chase ensued. The criminals lost control of the car. It crashed and caught fire. All four criminals were killed in the blaze. Homer Barley was later found alive.
It was later established that the criminals were associates of the loan shark known as Moldy Mink.
- Ambiguity in the artwork can make it difficult to differentiate between Arty Sidesaddle and Chic Complain. They have similar facial features and are both bald on the top of their heads. Initially, Arty was depicted without eyeglasses (which Chic wore). Later, Arty (the dark haired man) was depicted also wearing eyeglasses.
- When Arty's name was first identified, it was presented in quotation marks, indicating that it may be an alias.
- Arty and Chic were referred to as writers, but this did not prove to be relevant to their storyline.
- In his introduction to The Complete Dick Tracy Vol. 26, writer Max Allan Collins speculates that the last name "Sidesaddle" may have been meant to imply that the character was homosexual.
- In a later storyline, Dick Tracy referred to getting a tip from an informant named "Art Sidesaddle". There was apparently no connection between the characters.