In April 1849 he became commander of the Transylvanian Army Corps which needed to return to Turkey (7,000 infantry, 1,600 horse and 36 cannon). At the beginning of July he was moving into Hungary to (now ), to support Alexander von Lüders on the right flank. In this month there were a few battles between Lüders, Józef Bem and Sándor Gál. During the Transylvanian summer campaign, Clam-Gallas was defeated by Bem, but after that was able to defeat Sándor Gál and his Székels Army. After occupying Székely Land he joined Lüders and together they defeated Bem at Segesvár.