Working for Yonson
Yonson employed Joe for various odd jobs and errands around his errands. This occasionally included violence, such as when Yonson sent Joe to assault the photographer Lizz, who was cooperating with Dick Tracy and the police during the case of Oodles.
Joe Period was contacted by former attorney Paul Pocketclip, who wanted to Joe to convey a message of his affections to Julie Marrlin, an attractive singer at "Nothing" Yonson's nightclub. Julie's late husband had been a criminal that Pocketclip had defended. Pocketclip had attempted to bribe the judge in the case and was disbarred. Julie's husband was later found guilty and was executed.
The Julie Marrlin Case
Julie was amused by Joe when he approached, thinking he wanted an autograph, but when Pocketclip was mentioned, she revealed she blamed Pocketclip for her husband's death and refused to see him. Joe became attracted to Julie and he told Pocketclip about Julie's refusal. Pocketclip was frustrated but let Joe keep the hundred dollars he gave him for the job.
Pocketclip went to Julie's apartment with flowers and gifts, than threatened to shoot himself if she didn't give him the opportunity to woo her. Joe followed him, knocked away his gun and the two men struggled in the hallway outside Julie's apartment. Joe stabbed Pocketclip in the back of the head with an ice pick that he kept hidden on his person.
Joe hid in Julie's apartment while the police were called to investigate. He held a gun on Julie while she told the police through the door that she knew nothing about the murder. Julie's parakeet (which she kept uncaged) startled Joe and he shot it. The bullet also struck Julie. She was taken to the hospital where it was revealed that she was the sister of the new policewoman Lizz. Julie died from the gunshot wound.
Injury and Escape
Joe escaped by jumping out of a window in Julie's second floor room, landing on a car roof and fled in his own car that was nearby. During his escape, Period crashed his car and was badly injured. He fled to "Nothing" Yonson's nightclub, demanding to be hidden. Yonson stalled, pretending to call a doctor while Joe passed out from blood loss. Assuming the young man to be dead, Yonson and one of his men put the body in the case of an upright bass violin and threw it into an open car on a passing freight train.
The case was discovered by Doctor Forbes, a derelict who was riding the rails. He found Joe and administered first aid and whatever medical care he could. Finding a large supply of cash in Joe's wallet, Forbes took some money from the wallet and went into town when the train stopped and purchased food and supplies. When Joe finally roused and learned that Forbes had taken some of his money, he threw the old man off the moving train, killing him.
Dick Tracy and his squad were on Joe's trail at this point, and they tracked him to the train's next stop. Joe hopped the freight train and took refuge on a flat car that was transporting pickles. Joe hid in a huge vat of freezing pickles and brine. Unable to stand the cold, Joe called for help and was discovered by Lizz who identified herself as a police officer. Joe pulled her into the vat where she held him at gunpoint while yelling for assistance.
Meeting Flattop Jr.
The struggle was heard some passing children, who were soon chased off by an older boy. This turned out to be Flattop Jr, who pulled Joe from the vat, stranding Lizz. Joe and Flattop became fast friends, and the pair attempted to drown Lizz by positioning the vat under a water tower and opening the spout. The two fled in Flattop's car. Lizz managed to tread water until the level rose to the open hatch at the top of the vat and she escaped.
Joe was impressed by the amenities that Flattop had installed in his car (refrigerator, stove, safe, television, record player, running water) and the two succeeded in evading capture. Joe attempted to double-cross Flattop and steal his car at one point, but was foiled by Flattop's hidden parking brake. Joe was seemingly able to convince Flattop that it was a joke, and the two made their way back to the city.
In Joe's absence, "Nothing" Yonson had become increasing paranoid, fearing retribution. He refused to leave his office, had meals delivered to him, slept with a shotgun within arm's reach, and posted a 24-hour guard outside his door. Joe convinced Flattop to help him get revenge on Yonson, and the two managed to break into Yonson's office undetected. The robbed his safe and Joe shot Yonson.
Unbeknownst to the criminal duo, Yonson's club was under electronic surveillance by the police. When Joe and Flattop were seen escaping through a window, Tracy and his squad converged on the scene. Flattop, remembering Joe's earlier attempt to steal his car, abandoned his partner and fled with Yonson's money. Yonson lived just long enough to identify Joe as the person who shot him. Joe Period was taken into police custody.
Facing three murder charges (Julie Marrlin, Paul Pocketclip, and "Nothing" Yonson), Joe was visited in prison by his mother. She blamed herself for his criminal life and begged his forgiveness. He refused and demanded that she be removed from the jail. Distraught, Joe's mother threw herself into the path of an oncoming truck and was killed. Joe did not seem affected.
- Although it was strongly implied that Joe would face execution for his crimes, a later installment of the Rogues' Gallery feature identified him as serving life in prison.
- It is unclear if Joe was ever held accountable for his killing of Dr. Forbes.
- The exchange between Joe Period and his mother is one of the earlier (and more heavy-handed) instances of social commentary to appear in the strip.
- It was stated by Tracy that Joe was "about 21", which would make him slightly older than Flattop Jr.
- Joe is one of the few characters in the strip to be shown going from a status of Henchman (to Nothing Yonson) to Villain in his own right.