Von Hasselblut was born in 1755 to an impoverished family with minor links to the aristocracy. His family influence was sufficient to have him appointed as a Fahnenjunker to IR Nr 4 in 1772. Von Hasselblut's probationary period was extended due to some minor acts of indiscretion, but he was finally commissioned as Leutnant in 1776, just in time to accompany his regiment to North America, where it formed part of the contract army hired by George III of Great Britain. IR Nr 4 although involved in many minor actions never saw a pitched battle in North America, following one such at Cowper's Crossing (October 1777), Hasselblut received a battlefield promotion to Oberleutnant, filling the vacancy left by the death of his Company Commander. Von Hasselblut received further promotion to Hauptman in 1784 on his return to ONW.
His experiences in North America seem to have matured von Hasselblut, and on his return home he applied himself to his military duties and studies. He was one of the leading agitators for military reform, indeed his oft-spoken views came close to ending his military career. Among the reforms von Hasselblut advocated was a simplification of the military uniform, the creation of a military train of artillery drivers and the establishment of a regular force of rifle-armed Jaeger.
While not claiming that von Hasselblut's voice was instrumental in the effecting of these reforms, they were all carried out by the time that the French Revolution dragged Ober Nord Westfalen into a European war.
Despite his preoccupation with matters military von Hasselblut found time to woo and marry Fraulein Gerda von Wacholz, the daughter of a major in the service of the Duke of Brunswick.
Following his marriage, von Hasselblut was promoted to Major in 1790, seeing service in the campaigns of Valmy and The Vosges. Von Hasselblut became an Oberstleutnant in 1796, taking command of II/IR Nr 4. In 1799 promotion to the rank of Oberst and the command of IR No 2 came to von Hasselblut, and finally in 1803 he was promoted to the rank of Generalmajor commanding the 1st Infantry Brigade of IRs 1 and 2.
War came again in 1806 when the ONW army joined forces with those of its historical allies, Brunswick and Prussia, Von Hasselblut participated in the disastrous campaign of that year, achieving possibly his finest hour at Jena, where the ONW constituted the left-flank guard. As the Prussian army collapsed, von Hasselblut had the Drum Major of IR Nr 4 assemble all the drummers he could find, and amidst the smoke, confusion and despair of a battle lost, had the drummers beat endless repetitions of the "Rally". The survivors of ONW's shattered regiments rallied on IR 4, and under von Hasselblut's determined leadership, made a fighting withdrawal clear of the battlefield. For this feat, von Hasselblut was made a Companion of the Order of the Rose, Drum Major Wessler was commissioned Leutnant and IR 4 was presented with a set of silver drums which are still in use today.
As a result of this campaign, ONW was obliged to join the Confederation of the Rhine. Von Hasselblut refused to serve, and was so placed on the half-pay list. In 1808 von Hasselblut left ONW and with just over two hundred 'refugees' (mostly from IR 4), made his way to Austria, where he took service with the Duke of Brunswick's Black Horde.
Von Hasselblut stayed with Brunswick throughout the campaign of 1809, and during the Duke's fighting retreat to the North German coast, was placed in command of the rear guard, where once again his gritty determination proved of invaluable service. Von Hasselblut took ship to England, where he left the Duke's service and was commissioned into the KGL. He spent the next years until 1814 serving as a Colonel of Infantry in the Peninsula. On Napoleon's abdication he returned home, where he took a leading role in not only re-building the army of ONW, but also in keeping it out of Prussia's clutches.
In 1815, ONW despatched almost its entire army, under the command of von Hasselblut, to join Wellington in Belgium. Unfortunately en-route it collided with a French Corps under the command of General de Division Jean-Luc Picard. In a bitterly fought encounter at Hasselt, just North of Maastricht, von Hasselblut defeated Picard, but his force had taken heavy casualties and was in no fit state to continue operations until it had reorganised. Reorganisation completed. von Hasselblut reached Wellington on the 20th June 1815, where his advance guard was fired upon by nervous British troops, who took the ONW uniforms for those of the French!
ONW formed part of the army of occupation of France until January 1817 when it returned home. Von Hasselblut retired to his country home and remains there with his wife and family.
Throughout his career, von Hasselblut took a keen interest in his soldiers' welfare, ensuring, pace the vagaries of the commissariat system, that their rations were sufficient and on time. He identified strongly with them and always used 'we' and 'us' when addressing them (rather than 'you fellows' and 'I'. He retained a strong interest in IR Nr 4, and once he had reached the rank of General Officer, they quickly became his 'go to' regiment.