On May 6, 1776, he was enrolled in the Izmailovsky Life Guards Regiment as a noncommissioned officer.

Engelhardt fought in the Russo-Swedish War of 1788–1790 as a captain in the Ryazan Musketeer Regiment.

He was wounded in the chest and right thigh at Fredrikshamn, and for his distinguished service was promoted to major.

In the 1812 campaign, he commanded the 2nd Brigade of the 8th Infantry Division and fought against the Austrians and Poles in Volhynia and in the pursuit of the retreating enemy from Lutsk to Volkovysk.

In 1813, he participated in the capture of Białystok and of Warsaw and fought at Lutzen and Bautzen, where a severe bullet wound in the left thigh caused heavy bleeding which forced him out of the action.