Mackenzie was born May 25, 1844, in Potosi, Wisconsin[1] and graduated from the United States Military Academy in 1864.

Mackenzie spent six years commanding a company of engineer troops at Willets Point, New York, that experimented in the use of torpedoes (a.k.a.

Called to Washington in 1895, he became Assistant to the Chief of Engineers in charge of all matters relating to river and harbor improvements.

He was a member of the general staff corps and War College Board when appointed Chief of Engineers on January 23, 1904.

[4] Mackenzie retired May 25, 1908, as a major general, he was recalled to active duty in 1917 at age 73 as Northwest Division Engineer serving again in Rock Island, Illinois.