Leonard secured the release of a number of prisoners, for whom he has become a patron saint, then, declining the offer of a bishopric— a prerogative of Merovingian nobles— he entered the monastery at Micy near Orléans, under the direction of Saint Mesmin and Saint Lie. Then, according to his legend, Leonard became a hermit in the forest of Limousin, where he gathered a number of followers. Through his prayers the queen of the Franks was safely delivered of a male child, and in recompense Leonard was given royal lands at Noblac, 21 km (13 mi) from Limoges. It is likely that the toponym was derived from the Latin family name Nobilius and the common Celtic element -ac, simply denoting a place. There he founded the abbey of Noblac, around which a village grew, named in his honour Saint-Léonard-de-Noblat.
According to tradition, prisoners who invoked him from their cells saw their chains break before their eyes. Many came to him afterwards, bringing their heavy chains and irons to offer them in homage. A considerable number remained with him, and he often gave them part of his vast forest to clear and make ready for the labours of the fields, that they might have the means to live an honest life.
In the 12th century, his cult rapidly spread, at first through Frankish lands, following the release of Bohemond I of Antioch in 1103 from a Danishmend prison, where the successful diplomacy was inspired by Leonard of Noblac. Bohemond, a charismatic leader of the First Crusade, subsequently visited the Abbey of Noblac, where he made an offering in gratitude for his release. Bohemond's example inspired many similar gifts, enabling the Romanesque church and its prominent landmark belltower to be constructed. About the same time Noblac was becoming a stage in the pilgrimage route that led towards Santiago de Compostela. Leonard's cult spread through all of Western Europe: in England, with its cultural connections to the region, no fewer than 177 churches are dedicated to him. Leonard was venerated in Scotland, the Low Countries, Spain, Italy, Switzerland, Germany, particularly in Bavaria, and also in Bohemia, Poland, and elsewhere. Pilgrims and patronage flowed to Saint-Leonard de Noblac.
Leonard or Lienard became one of the most venerated saints of the late Middle Ages. His intercession was credited with miracles for the release of prisoners, women in labour and the diseases of cattle. His feast day is November 6, when he is honoured with a festival at Bad Tölz, Bavaria. He is honoured by the parish of Kirkop, Malta on the third Sunday of every August.