Day was born in Ravenna, Ohio, one of the children of Emily Day and Judge Luther Day of the Ohio Supreme Court. He graduated with a Bachelor of Science degree from the University of Michigan in 1870, spent a year studying law with attorney and judge George F. Robinson, and then a year at the University of Michigan Law School. He was admitted to the bar in 1872 and settled in Canton, Ohio, where he began practicing law in partnership with William A. Lynch. For twenty-five years, Day worked as a criminal defense and corporate lawyer in the growing industrial town while participating in Republican politics. During these years, Day became a good friend of William McKinley. Day became McKinley's legal and political adviser during McKinley's candidacies for the Congress, the Governorship of Ohio, and the Presidency of the United States. After he won the Presidency, McKinley appointed Day to be Assistant Secretary of State under Secretary of StateJohn Sherman. Sherman was considered to be ineffective because of declining health and failing memory, and in 1898, President McKinley replaced Sherman with Day. Five months later, Day vacated his cabinet position to helm the United States Peace Commission formed to negotiate an end to the Spanish–American War with Spain. After the Spanish–American War was declared, Day had argued that the Spanish colonies, other than Cuba, should be returned to Spain, contrary to McKinley's decision that the United States should take over from Spain control of the Philippines, Puerto Rico, and Guam. Day, however, negotiated peace with Spain on McKinley's harsher terms. His final diplomatic effort was to lead the United States Peace Commission into Paris, Franceand sign the Treaty of Paris ending the war. He was succeeded at the Department of State by John Hay.
McKinley was assassinated in September 1901 and the Vice President, Theodore Roosevelt succeeded him as president. In 1903, George Shiras Jr. resigned from the United States Supreme Court and Roosevelt offered his Associate Justice position to William Howard Taft. Taft declined in order to remain in his post as governor of the Philippines. In February, Roosevelt nominated Day, who accepted. The United States Senate confirmed the nomination on February 23, 1903, and Day received his commission the same day. He assumed his seat on March 2, 1903. He served as Circuit Justice for the Seventh Circuit from March 9, 1903, to March 17, 1912, and as Circuit Justice for the Sixth Circuit from March 18, 1912, to November 13, 1922.
Day was an avid baseball fan. He is recorded as asking his clerk for "regular updates" during the bench hearing of Standard Sanitary Mfg. Co. v. United States about the final game of the 1912 World Series.
Retirement and death
Day retired from the court on November 13, 1922, and briefly served as an Umpire of the Mixed Claims Commission to Adjudicate War Claims against Germany. He died on July 9, 1923, on Mackinac Island in Michigan, aged 74. He was interred at West Lawn Cemetery in Canton.
Family
In 1875, Day married Mary Elizabeth Schaefer. They were married until her death in 1912, and were the parents of four sons -- William Rufus, Stephen, and Luther.
Important opinions authored by Day
Ware & Leland v. Mobile County, 209 U.S. 405 --held that contracts for the sales of cotton for future delivery that do not oblige interstate shipments are not subjects of interstate commerce
Bobbs-Merrill Co. v. Straus, 210 U.S. 339 --helped establish "first-sale doctrine" in United States copyright law
Muskrat v. United States, 219 U.S. 346 --held that there must be an actual controversy between parties for the Federal courts to have jurisdiction
Bauer & Cie. v. O'Donnell, 229 U.S. 1 --held that patent rights could not be extended by the holder by means of a licensing agreement.
Buchanan v. Warley, 245 U.S. 60 --held that municipal ordinances segregating neighborhoods were unconstitutional
Hammer v. Dagenhart, 247 U.S. 251 -- held that laws regulating child labor are beyond the scope of Congress's constitutional power under the commerce clause
