In 1819, he returned to his homeland to prepare a geographic survey for his school, but was detained by Ali Pasha of Ioannina, who employed him at his court as a military adviser.

In August 1824, after Ali’s death, together with his brothers Nikolaos and Zachos Milios, he travelled south and joined the ongoing Greek War of Independence.

Spyromilios was thus forced to remain a spectator of the garrison's disastrous attempt to sally and break through the Ottoman lines, during which his brother Nikolaos was killed.

Following the outbreak of the Crimean War, he supported Greek revolts in the Ottoman Empire, despite the neutrality forced upon Greece by Britain and France.

Retired from the Army, he returned to politics from 1859, and served as Minister of Military Affairs in the several cabinets: In 1864-1865, he was a member of the short-lived Council of State, while in 1872, he was elected speaker of the Greek Parliament.