At the time of Leopold's birth, Lorraine and Bar had been occupied by Louis XIV of France, forcing his parents to move into exile to Austria, where they lived under the protection of the Emperor.

His mother, trying to fulfil her husband's last wishes of returning her children to their patrimony, appealed to the Reichstag in Regensburg to restore her son to Lorraine.

On 13 October 1698 at the Palace of Fontainebleau, Leopold married Élisabeth Charlotte d'Orléans, the niece of Louis XIV, who had offered a dowry of 900,000 livres to the penniless Duke.

A number of crimes were punishable with death by burning, such as witchcraft, coin forgery, arson, and sexual acts "contrary to nature".

He tried to install his eldest daughter, Élisabeth Charlotte Gabrièle of Lorraine, as Abbess of Remiremont but failed due to the opposition of Pope Clement XI.

In 1708, Leopold had claimed the Duchy of Montferrat as the closest relative of his cousin, Charles III Gonzaga, erstwhile Duke of Mantua, who had been deposed and then died without male issue.

However, the Emperor had already promised Montferrat to the Dukes of Savoy but wishing to compensate the House of Lorraine, he gave the Duchy of Teschen in Silesia to Leopold.

[1] In 1710, Leopold and his wife visited Paris to attend the marriage of Élisabeth Charlotte's niece Marie Louise Elisabeth to the Duke of Berry, and were among the guests of the lavish banquet at the Palais du Luxembourg.

However, Leopold Clement died shortly afterwards at Lunéville and in his stead, the younger son Francis Stephen went to Vienna, where he married Maria Theresa.

Leopold and Élisabeth Charlotte had 14 children in just 16 years: Jérémy Filet, “The networks of Francis Taaffe, 3rd Earl of Carlingford and Irish Jacobite émigrés in the Duchy of Lorraine” in Eighteenth-Century Ireland 36, 2021.