His father probably gave him royal powers in Burgundy, but Lothair took them back upon reaching his majority. In 977, he accused Lothair's wife, Emma, daughter of Lothair II of Italy, of infideility with Adalberon, Bishop of Laon. The council of Sainte-Macre at Fismes (near Reims) exonerated the queen and the bishop, but Charles maintained his claim was driven from the kingdom, finding refuge at the court of his cousin, Otto II. Otto promised to crown Charles as soon as Lothair was out of the way and Charles did homage, receiving back Lower Lorraine.
In August 978, Lothair invaded Germany and captured the imperial capital of Aachen, but failed to capture either Otto or Charles. In October, Otto and Charles in turn invaded France, devastating the land around Rheims, Soissons, and Laon. In the latter city, the chief seat of the kings of France, Charles was crowned by Theodoric I, Bishop of Metz. Lothair fled to Paris and was there besieged. But a relief army of Hugh Capet's forced Otto and Charles to lift the siege on 30 November. Lothair and Capet, the tables turned once more, chased the German king and his liege back to Aachen and retook Laon.
As he had been a vassal also of Lothair, his acts on behalf of Otto were considered treason and he was thereafter excluded from the throne. On Lothair's death (986), the magnates elected his son Louis V and on the latter's death (987), Hugh Capet. Thus, the House of Capet came to the throne over the disgraced and ignored Charles. Charles' marriage to the lowborn daughter of a vassal of Hugh was championed by his opponents as a cardinal reason to deny him the throne. In order to have free hand towards France, he resigned his duchy to regency of his eldest son Otto. Charles made war on Hugh, even taking Rheims and Laon. However, on Maundy Thursday991 26 March, he was captured, through the perfidy of the Bishop Adalberon, and with his young second son Louis imprisoned by Hugh in Orléans, where he died a short while later, in or before 993.
In 1666, the sepulchre of Charles was discovered in the Basilica of Saint-Servais in Maastricht. His skin appears to have been interred there only in 1001, but that is not the date of his death, as some scholars assumed.
He married secondly (975) Adelheid, parentage unknown. Among their children were:
He may have married thirdly Bonne, daughter of Godfrey I, Count of Verdun.
Though Charles ruled Lower Lorraine, the Dukes of Lorraine (Upper Lotharingia) counted him as Charles I of Lorraine.