William Worrall Mayo was born May 31, 1819, in Salford, Lancashire, England, which was then situated in the ecclesiastical parish of Eccles, where he was baptized on October 24, 1819.

[3] Mayo spent a brief period of time in Buffalo, New York, before settling in Lafayette, Indiana, where he worked as a tailor (one of the vocations he had while in England).

He settled in Saint Paul, but returned to Indiana a short time later to bring his family to the Minnesota territory.

He brought his family to a village named Cronan's Precinct (near Le Sueur) along the Minnesota River where he became known as the "Little Doctor" because of his 5-foot-4-inch (1.63 m) stature.

Mayo tried his hand at a number of different activities including farming, operating a ferry service, and serving as a justice of the peace in addition to occasional medical duties.

After a flood in 1859, the family moved to a home on Main Street in Le Sueur, now known as the Dr. William W. Mayo House.

As the American Civil War began that same year, Mayo attempted to procure a commission as a military surgeon but was rejected.

Organizing a group of people from Le Sueur and St. Peter, Mayo headed out to New Ulm, where some of the worst fighting had occurred.

Makeshift hospitals in the city cared for people injured in the conflict, as well as refugees driven from farms in the area.

His wife opened her home and a nearby barn to harbor eleven refugee families back in Le Sueur.

In hopes of getting a body for dissection, Mayo, among other medical men, attended the hanging of 38 Native Americans in December 1862 for their role in the uprising.

In the 1890s, Mayo advocated unsuccessfully to create an artificial lake by damming Bear Creek where it enters the Zumbro River.

The event that is usually credited with beginning the "Mayo Clinic Story" happened on August 21, 1883, when a tornado devastated Rochester.

Mother Alfred Moes of the Sisters of St. Francis was convinced a full-fledged hospital was needed in Rochester and approached Mayo to head it.

As the practice grew, Christopher Graham, E. Starr Judd, Henry Stanley Plummer, Melvin Millet, and Donald Balfour were also invited to join it as partners.