In 1605 Grigori Petrovich Romodanovsky became part of the Boyarsky Duma, received the rank of okolnichy. In 1615 he received the rank of boyar. He participated in the Russian-Swedish war of the early 1590s, served as a voivode in the cities of Dedilov, Tula, Livny, Belgorod. Grigori Petrovich distinguished himself in the battle of Rakhmantsevo in 1608. He participated in repelling the attacks of the Polish-Lithuanian troops on Moscow (1618), served as voivode in Kostroma (1622) and Novgorod (1623-1626).