His father was Pierre Nicolas de Lasalle d’Augny, an officer in the French Royal Army and a knight of the Order of Saint Louis.

Being an officer in the French Army had always been a privilege of the nobility, but this was reversed by a government decree in 1792, to the point of forbidding people of aristocratic origins to have military command.

He justified his rapid progress and reputation when, at Rivoli, he spurred ahead with his entire cavalry—26 horsemen of the 22nd Horse Chasseurs.

A battery of 15 French guns blasted the Austrian dragoons, while two columns of infantry were led forward, supported by cavalry under Leclerc and Lasalle.

Likewise, the dispersed infantry on the Trambasore Heights were unable to hold once Lasalle and the French cavalry got in their midst.

On 21 July 1798, at the Battle of the Pyramids, the Turks, reassured by the easy refuge the village of Embabeh provided for them, resisted the efforts of the French Army.

He cut off the retreating army by taking a secret route through the Giza Pyramids, allowing Napoleon to crush his opponents.

Because of this bold move, Napoleon promoted Lasalle to Lieutenant Colonel of the 22nd Horse Chasseur Brigade and 7th Hussars.

[3][dubious – discuss] Napoleon merely ordered his Grand Marshal of the Palace, and aide, General Géraud Duroc to give Lasalle another 200,000 francs.

Lasalle went into immediate action at the Battle of Austerlitz, with the 1st Dragoon Division, under the command of Divisional General Louis Klein, in the Cavalry Reserve of Marshal Joachim Murat.

He then fought at Schleiz and Jena-Auerstedt, where he captured the King of Prussia's bodyguard and forced the Prince of Hohenlohe to retreat.

On 26 October 1806, Lasalle was in pursuit of Hohenlohe when he observed Prussian infantry northwest of his position, at the edge of the forest, near Zehdenick.

After fierce fighting, the Prussians managed to beat back Lasalle's hussars until cavalry reinforcements arrived.

Marshal Murat arrived at 10 a.m. and ordered Lasalle to cut the road from Gustow and to storm the northern gates of the city.

The next day Lasalle and his hussars marched to the fortress of Stettin, arriving well ahead of the main French force.

General Romberg's reply was predictable: "Tell your master that the town of Stettin was entrusted to my safeguard and that I shall defend it to my last man".

Having run out of Prussian territory, On 5 November, he marched into the neutral city-state of Lübeck, where he demanded money and food from the city authorities.

During the Battle of Golymin, General Lasalle led his legendary "Hellish Brigade" against a Russian battery of 12-15 guns.

Lasalle kept them within a short range from the Russian guns as punishment for their behaviour, standing 20 paces in front of his men, remaining motionless and calm, although under enemy fire.

The following day, their combined 9,000-strong army attacked a force of 4-5,000 men under Spanish General Cuesta, deployed along the Cabezón bridge to bar the road to Burgos against oncoming French divisions.

In the subsequent French attack, the Spanish cavalry fled and the infantry broke, whereafter Lasalle proceeded to Valladolid, which he occupied the same night.

Two days later, Lasalle reached Meza de Ibor and fought the Spanish troops, forcing them out of their defensive position on the Tagus.

He also attacked frontally, and before long his French dragoons were rolling over the centre of the Spanish army, which was attempting to flee in any way it could.

Then, the advance guard and Lasalle's light cavalry would pass into Lobau, together with the material needed to bridge the second arm to the left bank.

Outnumbered on the second day of battle, Napoleon ordered Lasalle and Espagne to defend a sector which the IV Corps had been thrust into.

On 5 July 1809, Lasalle fought at the Battle of Wagram commanding a Light Cavalry Division in the IV Corps of Marshal Masséna.

Lasalle was temporarily separated from his division so when he accidentally disturbed a battalion of enemy infantry, he charged them with the 1st Cuirassier Regiment.

Marulaz tried to avenge Lasalle by leading a hussar regiment against a square of Austrian infantry but was wounded in the attempt and had to be carried to the rear.