Patrick was born in Lewisburg, West Virginia and graduated from West Point in 1886. For three years he was at the Engineers School of Application, Willette Point, New York, graduating in 1889. He was promoted to 1st lieutenant shortly after graduation in July 1889.
From 1892 to 1895 he taught engineering at West Point. From 1897 to 1901 he was involved in Mississippi River improvements, and after two years in the office of the Chief of Engineers he returned to the West Point faculty in 1903. He was promoted to major in 1904. From 1907 to 1909 he was Chief Engineer for the Army of Cuban Pacification and then worked on river and harbor projects in Virginia from (1909-1912) and Michigan (1912-1916). (From 1910-1912, he was also a member of a board directing the raising of the USS Maine in Havana Harbor.) During this period he was promoted to lieutenant colonel (June 1910) and colonel (March 1916) and found himself in command of the 1st US Army Engineers serving on the U.S.-Mexico border in that same year.
In May 1918 he was appointed by General John J. Pershing to command the combined Air Service of the AEF (May 1918) and subsequently promoted to major (two star) general the following month (June 1918). He remained with the Air Service until June 1919, returning then to the U.S. and to various engineering duties, including Assistant Chief of Engineers in 1920.
He was reappointed Chief of the Air Service in October 1925 and retired from the Army in December 1927. The following year he published "The U.S. In the Air". From 1929 to 1933 he was Public Utilities Commissioner for the District of Columbia.