Gilibert received primary home education under his uncle Pastor Gemini’s guidance. From the age of 12, he began to show interest in studying nature, collected herbarium and mineralogical collection. Parents wanted him to become a priest, but Gilibert entered the medical faculty of the University of Montpellier in 1760. In early 1763, he obtained his Bachelor's degree, and in August became Doctor of Medicine, presenting his work "De nature medicatrice".
After receiving his official medical license, Gilibert began to practice medicine near Lyon. In 1768, he became Professor of Anatomy, Surgery and Natural History at the Lyon Medical College. While working as a doctor in Lyon, Gilibert widely used local plants. He took money for treatment only after the recovery of patients, and treated poor people free of charge. In 1768-1773, in addition to his professorial activity and medical practice, he studied history of natural sciences and nature of the local regions, examining old manuscripts, herbariums and other biological collections. Gilibert also took an active part in the public life, joined the Masons, and became an important political figure that provided him an opportunity to receive funds for the creation of a botanical garden in the Brotto quarter of Lyon.
In the 1770s, Anthony Tyzenhaus, treasurer of the Grand Duchy of Lithuania and administrator of royal estates, invited Gilibert to Grodno to organize a medical school. Gilibert created botanical garden in Grodno (today’s city park named after J.I. Gilibert). Soon, the garden was considered as the best in Europe along with the gardens in London and St. Petersburg, and received the honorary title of "Royal". Seeds and seedlings were sent from England, Austria and Russia. In 1778, the garden collection numbered about 2000 domestic and exotic species of plants. More than 500 of the planted plants had practical purpose: were used to produce a variety of drugs for hospitals and pharmacies of Grodno Medical Academy. At the same time, Gilibert taught medicine, surgery, veterinary medicine and natural science. He established a special anatomical theater within the Academy, which became one of the best theaters among other medical schools in Europe. Students studied there "the inner world" of a man and various animals. The first state zoological museum appeared first on the territory of Belarus, thanks to Gilibert.
Coming to Grodno, Gilibert brought a herbarium from the Mediterranean coast and France. Living in Grodno he collected plants from local and more remote environs and botanical gardens. Together with other teachers and students, he organized several expeditions to the outskirts of Grodno, Bialystok, Warsaw, Nesvizh, Novogrudok, Vilnius, Shchorsy, Vishneva. They collected a variety of plants, making a herbarium, zoological and mineral collection. The collected data provided basis for his 5-volume work "Flora of Lithuania." He planned to establish agricultural and veterinary schools, and together with Tyzenhaus to found the Academy of Sciences in Grodno.
When Anthony Tyzenhaus was removed from the position of the Grodno starosta (administrator), Gilibert was invited to Vilnius by Rector Marcin Odlanicki Poczobutt in 1781. He moved there in the late autumn of that year together with his students and took the collection of minerals, a library of 3,000 volumes, surgical instruments, astronomical and physical devices, most of the plants from the botanical garden. He was commissioned to establish the Natural History Department and the Botanical Garden. Gilibert created Medical Faculty at Vilnius University using materials from the Grodno Medical Academy. He headed the Department of Natural History and Botany there. Living in Vilnius, he herbarised plants of Vilnius environs and the Botanical Garden. Before coming to Vilnius he had also the experience in founding the botanical garden in Lyon (France) and in Grodno (Belarus); so he was proficient head of the garden. Location of the first Botanical Garden in Vilnius was in the heart of the town, in the courtyard of the Medical College (Collegium Medicum), in a small plot of about 200 square metres. In early spring of 1782, the majority of plants were moved from Grodno Botanical Garden to the newly founded Vilnius University Botanical Garden. Plants, in that time known as hard for Lithuanian climate conditions, were planted outdoor into soil beds. Others were planted in a small, quickly built greenhouse. There is no accurate data how many plants were moved from Grodno to Vilnius and how many plants were cultivated by Gilibert in Vilnius University Botanical Garden. The claims of some authors that soon about 2.000 species of plants had been gathered should be evaluated carefully. Doubts about such numbers appear mainly due to the lack of a single authentic document prepared by Gilibert to confirm this fact. The plants he left had been taken over by G. Forster, the second director of Botanical Garden, only after two years from departure of Gilibert from Vilnius. Today we can discuss only about one archive source of the 18th century to approximately assess the plant collection accumulated by Gilibert in Vilnius, i.e. G. Forster’s manuscripts (kept in the archive of the Göttingen University). The takeover inventory of the Gilibert collection of garden plants (more exactly, seeds) compiled in May of 1785 in Vilnius by G. Forster contains 350 items.
Gilibert returned to Lyon in 1783 and worked as an epidemiologist. After departure of Gilibert from Vilnius, some herbaria had been sent to France, but quite a few remained in Vilnius. In 1792, he was a Professor of Natural History of the Institute of Sciences and Arts. During the Great French Revolution (1789-1794), Gilibert was arrested by the Jacobins for belonging to the Girondins in 1793. In the same year, he was released and elected Mayor of Lyon. After the defeat of the revolution, he left politics and engaged in science.
During the Great French Revolution of 1789-1794, Gilibert was arrested by the Jacobins for belonging to the Girondins in 1793. In the same year, he was released and elected Mayor of Lyon. After the defeat of the revolution, he left politics and engaged in science.
While working as a doctor in Lyon, Gilibert took money for treatment only after the recovery of patients, and treated poor people free of charge.