He attended the common schools and Clinton Liberal Institute, and graduated from Mexico Academy, New York, in 1866.

He served as member of the Board of Visitors to the United States Military Academy at West Point in 1884.

On September 6, 1901, Skinner was attending the Pan-American Exposition in Buffalo, New York to hear President McKinley give a speech about reciprocity.

McKinley died of his wounds on September 14, 1901, becoming the third President to be assassinated after Abraham Lincoln in 1865 and James Garfield in 1881.

In 1919, Skinner wrote an account of his experiences with McKinley, and of the events which occurred on the day of the execution of Czolgosz.

The article documents Czolgosz's last words: "The reason I killed the President was because he was an enemy of he good people-for the benefit of the working man.