He reached the rank of lieutenant colonel in the Serb militia forces in the Pomorišje region, then in the Military Frontier of the Habsburg monarchy.

When it became obvious that privileges granted to Serb militiamen would be reduced or completely revoked after Pomorišje and Potisje lost their frontier status, Šević left Habsburg military service in 1750 and moved to Russia.

At the end of 1752, he led the second wave of colonists who migrated from Pomorišje, Potisje and Slavonia to the Russian Empire (modern-day Ukraine) where they settled the newly established administrative region of Slavo-Serbia at the beginning of 1753.

[7][8] Đurka succeeded Jovan Tekelija in this position in the first half of 18th century, while at that time, his son was an oberkapitän in Čanad (modern-day Magyarcsanád).

In the November 1750 plebiscite, he was the first higher-ranking officer who left the Habsburg army; he applied to be regular citizen and requested a passport to emigrate to Russia.

[14] To avoid issuing the passport to Šević, the government officials staged a trial against him and arrested him,[15] but eventually lost the case because of the lack of evidence for their accusations.

When the prosecution lost their case because of the lack of evidence, Horvat left their side and became one of the most ardent supporters of migration to Russia.

[16] To prevent emigration of a larger number of Serbs to Russia, Habsburg Empress Maria Theresa issued a special decree (German: Pönal-Patent) on 19 June 1752.

[17] The Russian empress Elizabeth promoted Šević to the rank of General with the right to appoint other subordinated military officers who would join him to migrate to Russia.

They refused to do so and Šević accompanied by Rajko Preradović, a Colonel of the Slavonian Hussar Regiment, went to St. Petersburg where they submitted an application to the Governing Senate to allow them to settle another territory, separated from New Serbia.

On 17 May 1753, Russian empress Elizabeth signed a decision to allow colonists from Pomorišje led by Šević to populate the territory between Bakhmut and Luhansk.