Gary, Indiana, was founded in 1906 by the United States Steel Corporation as the home for its new plant, Gary Works. The city was named after lawyer Elbert Henry Gary, who was the founding chairman of the United States Steel Corporation.

Gary was the site of civil unrest in the Steel Strike of 1919. On October 4, 1919, a riot broke out on Broadway, the main north-south street through downtown Gary, between striking steel workers and strike breakers brought in from outside. Three days later, Indiana governor James P. Goodrich declared martial law. Shortly thereafter, over 4,000 federal troops under the command of Major GeneralLeonard Wood arrived to restore order.[12]

The jobs offered by the steel industry provided Gary with very rapid growth and a diverse population within the first 26 years of its founding. According to the 1920 United States Census, 29.7% of Gary's population at the time was classified as foreign-born, mostly from eastern European countries, with another 30.8% classified as native-born with at least one foreign-born parent. By the 1930 United States Census, the first census in which Gary's population exceeded 100,000, the city was the fifth largest in Indiana and comparable in size to South Bend, Fort Wayne, and Evansville. At that time, 19.3% of the population was classified as foreign-born, with another 25.9% as native-born with at least one foreign-born parent. Gary was also becoming increasingly racially diverse, with 17.8% of the population classified as black, and 3.5% as Mexican.