Kovalyak served with the MFAA following the Allied victory in Europe. He worked primarily in the field, evacuating repositories filled with stolen and hidden artworks. At Alt Aussee, Kovalyak worked with a team of MFAA officers under the direction of Lt. Comdr. George Stout and Lt. Comdr. Thomas Carr Howe. According to Howe, “George had a fatherly affection for Steve and a quiet admiration for his energy and resourcefulness and the way he handled the men under him.” While working in the salt mines of Alt Aussee, Kovalyak packed and transported some of Europe’s greatest masterpieces that had fallen victim to Hitler and the Nazis, such as theBruges Madonna, the Ghent Altarpiece, and the Rothschild Jewels. He also assisted in the early packing of the Veit Stoss Altarpiece in Nuremberg, and of countless other artworks at Nazi repositories discovered by Allied forces in Siegen, Bernterode, and Berchtesgaden. Kovalyak was later honored by the Polish government for his work with the MFAA.