[2] Conrad's father took advantage of the conflict between King Henry IV of Germany and the Swabian duke Rudolf of Rheinfelden during the Investiture Controversy.

When Rudolf had himself elected German anti-king at Forchheim in 1077, Frederick of Hohenstaufen remained loyal to the royal crown and in 1079 was vested with the Duchy of Swabia by Henry IV, including an engagement with the king's daughter Agnes.

Emperor since 1111, Henry V prepared for his second campaign to Italy upon the death of Margravine Matilda of Tuscany, and in 1116 he appointed Conrad as Duke of Franconia.

[7] Conrad quickly crossed the Alps to be crowned King of Italy by Anselmo della Pusterla, Archbishop of Milan, in the village of Monza.

[8] Over the next two years, he failed to achieve anything in Italy, however, and returned to Germany in 1130, after Nuremberg and Speyer, two strong cities that supported him, fell to Lothair in 1129.

[9] After Lothair's death (December 1137), Conrad was elected king at Coblenz on 7 March 1138, in the presence of the papal legate Theodwin.

[10] As Henry the Proud, son-in-law and heir of Lothair and the most powerful prince in Germany, who had been passed over in the election, refused to do the same, Conrad deprived him of all his territories, giving the Duchy of Saxony to Albert the Bear and that of Bavaria to Leopold IV, Margrave of Austria.

In 1146, Conrad heard Bernard of Clairvaux preach the Second Crusade at Speyer, and he agreed to join Louis VII in a great expedition to the Holy Land.

At the imperial diet in Frankfurt in March 1147 Conrad and the assembled princes entrusted Bernard of Clairvaux with the recruitment for the Wendish crusade.

Conrad fell seriously ill at Ephesus and was sent to recuperate in Constantinople,[15] where his host the Byzantine Emperor Manuel I Comnenus acted as his personal physician.

Frederick Barbarossa, who had accompanied his uncle on the unfortunate crusade, forcefully pursued his advantage and was duly elected king in Cologne a few weeks later.