Jean-Baptiste Gellé, born 23 July 1777 in Créhange (Lorraine, France) can be considered one of the founding fathers of Luxembourg as we know it today. Gellé's family moved to Luxembourg in 1786. His father, a merchant, had become a citizen of the City of Luxembourg, and belonged to the merchant guild. Gellé studied at the prestigious Luxembourg Athenaeum. His life was marked by his experiences of living through France's Ancien Régime in his youth, the First French Republic as a young man, the Belgian Revolution, and the establishment of the Grand Duchy of Luxembourg as its own sovereign nation in 1839. On 1 November 1796, while the country was still under French rule, he became undersecretary for the City of Luxembourg. Barely a year later, Gellé moved to the country's central administration and, before long, was appointed to the position of Bureau Chief, and later Division Chief, in the Département des Forêts prefecture, whose jurisdiction covered the entire country. Soon after joining the administration, he was inducted into the "Enfants de la Concorde fortifiée" masonic lodge, where he would serve as Grand Master no fewer than five times between 1815 and 1846. Jean-Baptiste Gellé co-founded the Cercle Constitutionnel (Constitutional Circle) to promote the principles of freedom and republicanism.

Despite the fall of Napoleon I, Gellé went on to have a stellar career. Jean-Georges Willmar, the Governor of Luxembourg – a former MP and Special Advisor for the Département des Forêts – kept Gellé on, even promoting him to the position of Secretary General of the Government, and subsequently Registrar for the Provincial States.

Believing that knowledge was the main driver of peace, prosperity and progress, Gellé was a strong promoter of education. In 1817, he proposed to set up schools throughout the country, staffed by teachers who had been trained to the highest standards. The central administration set up a temporary commission on which Gellé would serve as secretary. The aim was to persuade municipal authorities either to establish new schools or to improve the education on offer at their existing ones, make teaching more attractive as a career option and raising the level of education dispensed. Alongside his role as Secretary of the Provincial Commission for the Administration of Primary Education, Gellé would also serve as School Inspector for the district of Luxembourg. Many of Luxembourg's regulations were drafted by Gellé.

The Belgian Revolution in 1830 would disrupt all of these schemes, and Gellé, despite being a proponent of the Orangist movement, joined the board of administration of the Luxembourg Athenaeum. Between 1830 and 1835, he remained in post as Government Registrar, and then joined the Government Commission, whose remit was restricted to the City. During the Belgian Revolution, only the capital of the Grand Duchy remained under the control of the King-Grand Duke. The rest of the country fell under Belgian authority. In 1840, William II appointed Gellé to the committee tasked with drafting the Luxembourg constitution, and entrusted him with official duties. He accepted the senior position of Head of the Civil Service. In 1843, he chaired the committee in charge of implementing the new education law. In 1845, the electors in the canton of Luxembourg appointed Gellé as a member of the States of Luxembourg. On 16 March 1847, Gellé, who was then Advisor to the Government, died suddenly at his home on Rue du Marché-aux-Herbes. Thousands of people, including all the nobility in the canton, came to pay their respects during his funeral procession. As he died a bachelor, his estate went to his sister, Catherine, of whom Gellé had been extremely fond. Even during his lifetime, Gellé received accolades for his talents: in 1822, William I, King of the Netherlands, awarded him the Order of the Netherlands Lion. The King's successor, William II, raised Gellé to the rank of Commander of that order, and also conferred upon him the insignia of Commander, and subsequently Knight of the Order of the Oak Crown. The King of the Belgians named him Commander of the Order of Leopold. Through her will, dated 29 April 1874, Catherine Gellé (1778–1876), Jean-Baptiste's sister, left her fortune to the City of Luxembourg and to the social welfare office, with a view to setting up a "J.B. Gellé" scholarship for poor children from the city. Any additional revenue each year was to go towards improving the lot of those in direst poverty. The Fondation Gellé (Gellé Foundation) was officially recognised by Grand-Ducal decree on 30 October 1878. The City of Luxembourg also named a street in honour of J.B. Gellé. Only the Church denied him the final honours. On 16 March 1848, a roll of the members of the Freemasons was laid on J.B. Gellé's grave to mark the first anniversary of his death. In July 1848, the periodical, Der Volksfreund, published a biography of Gellé in six parts. Thanks to gifts and bequests from Catherine Gellé, the City of Luxembourg has retained ownership of J.B. Gellé's burial plot.