Cummins' successes included establishing the direct primary to allow voters to select candidates instead of bosses; outlawing free railroad passes for politicians; imposing a two-cent street railway maximum fare; and abolishing corporate campaign contributions.

[4] At age nineteen, Cummins came with his maternal uncle to Elkader, Iowa, finding employment in the Clayton County recorder's office and also worked as a carpenter.

[4] At first, Cummins mainly represented businessmen in court, thus improving his finances and achieving prominence in Des Moines' high society.

[6] However, historians consider his representation of farmers in the barbed wire case to be an anomaly because more often he represented corporations or businessmen.

In early 1900, when the Iowa General Assembly exercised its former power to choose a U.S. senator for the Class 2 seat, to serve from 1901 to 1907, Cummins was the opponent of incumbent Republican John H. Gear, but withdrew when it appeared he lacked the votes to win.

[9] Cummins initially vowed to seek the seat again in the 1901 legislative session,[9] but instead focused on winning the 1901 election for governor of Iowa.

[7] While governor he led efforts to establish compulsory education, a state department of agriculture, and a system of primary elections.

[4] In June 1908, Governor Cummins ran in the Republican primary for the U.S. Senate seat held by William B. Allison, who was seeking a record seventh term.

Cummins generally supported President Woodrow Wilson's initiatives to regulate business, and authored a clause of the Sherman Antitrust Act.

[3] It was as Interstate Commerce Commission chair that Cummins sponsored the Esch-Cummins Act of 1920, establishing the conditions for the return of the railroads to private control[2] after their government operation during World War I.

[7] Labor activists complained that the bill perpetuated harsh limits on collective bargaining, including provisions making it a crime to encourage a railroad strike, in the absence of a wartime emergency.

After Cummins again finished fifth on the second ballot, he released his delegates, contributing to the third-ballot victory of Supreme Court Justice Charles Evans Hughes.

[23] However, he gradually turned more conservative moving from La Follette's Progressivism to the New Era Republicanism of Warren G. Harding.

[3] His wife, Ida L. Cummins, was an activist in the suffrage movement and very influential in the development of Iowa child labor laws.