At least six former members of the Belaia garrison, including George Learmonth, helped decisively turn back Prince Wladyslaw’s troops in intense fighting at Moscow’s Arbat Gates of Bely Gorod during defending Moscow against a Polish army.

When Lieutenant David Edwards was killed in the defence of Moscow, the Irish soldiers in his company immediately petitioned to have George Learmonth replace him.

During the Smolensk War (1632–1634) he's Rittmeister of Moscouvite Reiters regiment of Charles d'Ebert,[1] under command of Prince Semyon Prozorovsky, died in battle against units of Field Hetman of Lithuania Krzysztof Radziwiłł on 30 August 1633.

[3] George was the brother of Peter-Patrick Learmonth (born about 1596), who was captured by the Poles whilst in Swedish service, fighting on behalf of Muscovy during Russians hostilities with Poland 1614-1616.

No records have survived concerning George's early career, but it is likely that he was swept up in his kinsman James Spens's large-scale recruiting campaign.