On the late evening of Saturday, September 6, 1924, John Herbert Dillinger's career in crime started inauspiciously enough with the botched robbery attempt of a grocer in his hometown of Mooresville, Indiana. Dillinger had turned 21 years of age just three months earlier. After playing two baseball games in Martinsville, the county seat, he was driven home by Edward Singleton, a distant cousin related to his stepmother and an umpire that traveled with the Martinsville team. Each team supplied one umpire. Singleton, an individual who had a knack for finding trouble, decided to expose John to some bootleg brew. After getting John fully intoxicated Singleton prepared John for the robbery of grocer Frank Morgan. The elderly Morgan was a friend of the Dillinger family and owner of the West End Grocery; a store that John Sr. sold farm goods to. Singleton pulled the car into an alley near the Christian Church and placed John in a dark inlet of the church near the side stairs. John was so drunk he could barely walk. Singleton gave John a bolt wrapped in a handkerchief. Singleton propped John up and hit the horn twice as Morgan passed Singleton's car halfway down the alley. That was the signal for John to attack Morgan. John came out of the inlet and hit Morgan on the head. At this point the 65 year-old grocer began to wrestle with the young and drunk John. He had John on the ground when Singleton came out of the car and shot his gun once into the air. This startled both Dillinger and Morgan. Dillinger got up and was confused. Eventually he rushed toward the car which Singleton was now backing down the alley. Morgan then screamed out the KKK (possiblyy the Masonic) scream for help and porch lights came on. Dillinger headed up town and poked his head in the pool hall to ask if Mr. Morgan was okay. Of course no one knew if he were as the incident had just happened but John was too drunk to know what he was asking.
John was sent to the reformatory in Pendleton, Indiana, where he was to meet future colleagues Harry Pierpont and Homer Van Meter. After serving five years without parole, an embittered Dillinger requested and received a transfer to the Indiana State Prison in Michigan City, Indiana, where Pierpont and Van Meter were already in residence.
By mid-1932 Dillinger had become part of a group of prisoners intent on escaping. This group included Harry Pierpont as one of the leaders, along with Charles Makley, John Hamilton, Russell Clark, and later Walter Dietrich and James Jenkins. Since Dillinger's parole date was approaching he was selected to operate as their connection on the outside, carrying out robberies to raise funds for the escape.
Subsequent to his parole on May 22, 1933, he began a series of holdups. During this period Dillinger began to call attention to himself with his flamboyant style, which included wearing a fashionable straw hat, and a knack for athletic leaps over the teller's barrier into the cashier's cage. Not long after securing sufficient funds for the necessary bribes of guards and officials, along with arranging for the smuggling of weapons into the prison, he was once again arrested in Dayton, Ohio. The arrest took place on September 22, 1933, at the boarding house room of girlfriend Mary Longnaker, with whom he had visited the Chicago World's Fair that summer.