From the 1890s to the 1920s, Marshall was a founder or president of companies related to bridge construction, road paving, public utilities, railroads, and grain storage.

[1] As president of the Western Construction Company, Marshall was indicted in 1908 when an employee overcharged the city of Indianapolis for a paving job.

[1] The Evansville Courier was another Indiana newspaper company that he bought that year; he sold it to Mayor Benjamin Bosse a few months later.

In 1932 Marshall led a group that convinced the Indiana Republican convention to support the repeal of the Eighteenth Amendment to the United States Constitution, which had prohibited the sale of alcoholic beverages.

[1] By the time of his death in 1951, Marshall owned 6,000 acres (2,400 ha) of farm land near his home in Lafayette, Indiana.