By 1864 he had been promoted to the rank of Major General (Generalleutnant) and given command of the 6th Infantry Division, which he led during the Second Schleswig War in the Battle of Dybbøl and at Als.

During the Austro-Prussian War he commanded the reserve of the First Army, which he led during the battle of Königgrätz and for which he was awarded the Pour le Mérite.

In 1867, Manstein was given command of IX Corps and was promoted to General der Infanterie in 1868.

When the Franco-German War started in August 1870, IX Corps became part of the Second Army of Prince Friedrich Karl.

After the fall of the Second Empire, Manstein fought in the Loire Valley in the campaigns at Orleans and Le Mans.