Appropriately for one who came from a family with a long tradition of military service, it was during the American Civil War that Harrison really made a name for himself and laid the foundation for his future career in politics. Before the war he had practised law in Indianapolis, but during the years of conflict he distinguished himself" in his country's service, rising from Colonel to Brigadier General, taking part in Sherman's famous march through Georgia.

In 1880 he was elected to the US Senate where served until being elected President, taking up office in March 1889.

A number of important pieces of legislation were passed during his one term of office, including the Disability Pension Act and the Sherman Anti-Trust Act. Harrison was defeated by Cleveland in the presidential election of 1882, returning to practice la·sv. He died from pneumonia on 13 March 1901 in Indianapolis, Indiana.