While little is known of Ghesquière's early life, it is established that she joined the French army in 1806. Ghesquière elected to take her brother Jean Baptiste's place in the French army, disguising herself as a man. Accounts vary as to whether her brother died in battle and she replaced him masquerading as another brother, or if she represented herself as Jean Baptiste himself in order to enlist. Regardless, Ghesquière served in the 27th Line Regiment of the army for 6 years.
Ghesquière had a distinguished military career serving in a number of campaigns during the Napoleonic Wars. In 1807 she took part in the invasion of Portugal during the Peninsular War, serving under General Jean-Andoche Junot. Distinguished numerous times for her performance, Ghesquière was promoted to Sergeant for her bravery at the Battle of Wagram, where she saved her captain from drowning in the Danube river. She was also commended for saving the life of a colonel who had fallen from his horse after being shot.
Ghesquière was injured in battle in 1812 and the surgeon treating her wounds discovered her identity as a woman. This led to her immediate dismissal from the army. However for her contribution in the war she was awarded the French Legion of Honor medal by Napoleon himself.
Ghesquière's dismissal from the army brought her a small amount of fame and she was featured in an article of the Journal de l'Empire newspaper. There was also a song composed about her life, which referred to her as the 'jolie sergent' (pretty sergeant). Although her year of birth is unknown, Ghesquière is believed to have been over 100 years old when she died in 1854.