Once he returned home in 1774, he was instructed to be a mathematics instructor to a high ranking generals daughter. Eventually, he fell in love with one of the daughters, Ludwika, and tried to get her to elope with him. To avoid further conflict he fled to France. Then, in 1776 he traveled to the Colonies to help fight for their independence from Great Britain. He was sent to Pennsylvania to help plan fortifications to protect the Continental Congress. Since he excelled at this, he was then promoted to engineer colonel. Then, in 1777 he was he was transferred to the army of General Horatio Gates at Fort Ticonderoga, in upstate New York. He was very active in Gates's and worked to close all roads that were along the Hudson River. This contributed to the success of General John Burgoyne against enemy forces at Saratoga. Once this was done, he spent the following couple years helping to fortify West Point. For his excellent work, he was then promoted to chief of the engineering corps.
For his part in the war effort, he was given citizenship to the new United States and was also made a brigadier general in the US Army. After the end of the Revolution he returned to his homeland of Poland. When he was home he was not allowed to join the military due to his past trials with the general he used to work for. He lived in poverty on a small estate for the next five years of his life. He was only able to join the military again after there were reforms to the country and once he had protection from his former lover, Ludwika. Once back in the military he was given the rank of general major and once again found himself in love an eighteen year old noblewoman. He would once again try to get her elope, but just like before, he father wouldn't let this happen. After this happened, he began different conquests that included Prussia, Russia, and eventually he was taken captive as a prisoner of war.
When the general was released from the prison in 1797, he traveled back to the country in which he helped to gain its independence, the United States. He arrived in Philadelphia and was greeted by a crowd of people. During his time back he found himself going to different social events and sticking around with different social groups. He ended up becoming close friends with then Vice President, Thomas Jefferson. He then secretly left the States as he found out that there might be some possibility to help promote Poland in their cause in France. Before he left however, he gave instruction for his slaves to be freed and they were to educated. After his different failures throughout the years in France and talks with Napoleon, the General eventually died in 1817. He was buried within the kings tombs within the cathedral and true to custom, a huge mound was erected to preserve his memory.