After one year serving in the army, he studied law in Lausanne, Munich, and Berlin, and in 1901 joined the Foreign Office's consular service as a junior civil servant (Assessor).

With the outbreak of the First World War in 1914, Schulenburg returned to the military, and after the First Battle of the Marne was promoted to captain in October 1914 and put in charge of an artillery battery.

After the German Empire's collapse, he was captured by the British and interned on the Mediterranean island of Prinkipo (now called Büyükada).

Schulenburg served as the German ambassador to Iran from 1922 until 1931, when his visit to the ancient monuments at Persepolis resulted in his name being engraved at the Gate of All Nations.

Schulenburg favoured an agreement between Germany and the Soviet Union, and was instrumental in bringing about the German-Soviet Non-Aggression Pact of August 1939.

To the last, he tried to thwart any talk of invasion by such means as hinting at the Soviet Union's military strength and the unassailability of its industrial reserves.

He is quoted as having said to Molotov on the morning of the attack: "For the last six years I've personally tried to do everything I could to encourage friendship between the Soviet Union and Germany.

[5] After the German invasion began on 22 June 1941, Schulenburg was interned by the Soviets for a few weeks and was transferred to the Soviet-Turkish border for repatriation.