Alexander originally Sándor von Wagner was a Hungarian painter.

Wagner was born in Pesth. After graduating from the Real-Gymnasium in his hometown at the age of nineteen, he entered the Academy of Fine Arts at Vienna, where he was a student of Henrik Weber. The following year, he switched to the Royal Academy of Fine Arts at Munich and was taught by Professor Karl von Piloty from 1856 to 1864. From 1869 to 1910 he was professor in history painting at the Munich Academy. His themes were history paintings and Hungarian life scenes in particular. A portrait of Von Wagner painted by Franz Lachner belongs to the collection of the Gebrüder-Lachner-Museum in Rain since 2003. Among his students were Pál Szinyei Merse, Emil Wiesel, Anton Ažbe, Franciszek Żmurko.

Von Wagner died in Munich, where he is buried in the Old Southern Cemeterey.