He was active in numerous campaigns during a period of 47 years (1498–1544), including the German Peasants‘ War, besides numerous feuds; in his autobiography he estimates that he fought 15 feuds in his own name, besides many cases where he lent assistance to friends, including feuds against the cities of Cologne, Ulm, Augsburg and the Swabian League, as well as the bishop of Bamberg.
In 1497, Berlichingen entered the service of Frederick I, Margrave of Brandenburg-Ansbach. In 1498, he fought in the armies of Holy Roman Emperor Maximilian I, seeing action in Burgundy, Lorraine, and the Brabant, and in the Swabian War the following year. By 1500, Berlichingen had left the service of Frederick, and formed a company of mercenaries, selling his services to various Dukes, Margraves, and Barons.
In 1504, Berlichingen and his company fought for Albert IV, Duke of Bavaria. During the siege of the city of Landshut, he lost his right arm when enemy cannon fire forced his sword against him. He had a mechanical prosthetic iron replacement made, which is today on display at the Jagsthausen Castle. This prosthetic hand was ahead of its time, being capable of holding objects from a sword to a feather pen. In spite of this injury, Berlichingen continued his military activities. In the subsequent years he was involved in numerous feuds, both of his own and in support of friends and employers.
In 1512, near the town of Forchheim, due to a long running and bitter feud with Nuremberg he raided a group of Nuremberg merchants returning from the great fair at Leipzig. On hearing this, Emperor Maximilian placed Berlichingen under an Imperial ban. He was only released from this in 1514, when he paid the large sum of 14,000 gulden. In 1516, in a feud with the Principality of Mainz and its Prince-Archbishop, Berlichingen and his company mounted a raid into Hesse, capturingPhilip IV, Count of Waldeck, in the process. A ransom of 8,400 gulden was paid for the safe return of the count. For this action, he was again placed under the ban in 1518.
In 1519, he signed up in the service of Ulrich, Duke of Württemberg, who was at war with the Swabian League. He fought in the defence of Möckmühl, but eventually was forced to surrender the town, owing to a lack of food and ammunition. In violation of the terms of surrender, he was held prisoner and handed over to the citizens of Heilbronn, a town he had raided several times. His fellow knights Georg von Frundsberg and Franz von Sickingen successfully argued for his release in 1522, but only after he paid a ransom of 2,000 gulden and swore not to take vengeance on the League.
In 1525, with the outbreak of the German Peasants‘ War, Berlichingen led the rebels in the district of Odenwald against the Ecclesiastical Princes of the Holy Roman Empire. Despite this, he was (according to his own account) not a fervent supporter of their cause. He agreed to lead the rebels partly because he had no other option, and partly in an effort to curb the excesses of the rebellion. Despite his wishes to stop wanton violence, Berlichingen found himself powerless to control the rebels and after a month of nominal leadership he deserted his command and returned to the Schloss Jagsthausen to sit out the rest of the rebellion.
After the Imperial victory, he was called before the diet of Speyer to account for his actions. On 17 October 1526, he was acquitted by the Imperial chamber. Despite this, in November 1528 he was lured to Augsburg by the Swabian League, who were eager to settle old scores. After reaching Augsburg under promise of safe conduct, and while preparing to clear himself of the old charges against him made by the league, he was seized and made prisoner until 1530 when he was liberated, but only after repeating his oath of 1522 and agreeing to return to his Burg Hornberg and remain in that area.
Berlichingen agreed to this, and remained near the Hornberg until Charles V, Holy Roman Emperor, released him from his oath in 1540. He served under Charles in the 1542 campaign against the Ottoman Empire of Suleyman the Magnificent in Hungary, and in 1544 in the Imperial invasion of France under Francis I of France.