In the War of Polish Succession Lentulus participated in the 1734 campaign in Italy as the adjutant of the Field marshal, Count Claude Florimond de Mercy, who fell on 28 June in the Battle of San Pietro (sometimes called the Battle of Parma). In 1735, he joined the campaign in the Rhineland. He fought later in the Austro-Turkish War of 1737–39 and from 1742–44 in the campaigns in Bavarian and Bohemia during the War of Austrian Succession. Lentulus was also consulted on military-diplomatic negotiations after the armistice of 1735 and the border regulation between the Banat and Serbia after the Belgrade Peace. When the opportunity arose, Lentulus undertook lengthy journeys in Italy and the Orient.