Ernst Karl Eugen Koerner was a German landscape painter.

His father, Ernst (1794-1856) was a cloth dealer. In 1861, while still attending the public schools, he began working in the studios of Hermann Eschke, where he received most of his artistic education. Later, he also worked for Karl Steffeck and Gottlieb Biermann [de]. He spent most of the two following decades travelling; to the North Sea, the Baltics, the Harz Mountains, France, England, Italy, Scotland and Spain. From 1873 to 1886, he made numerous trips to Egypt and the Middle East, where he created some of his best known paintings.

In 1874, he married Auguste Heyl (1855-1899), the daughter of a factory manager. They had one daughter and three sons, including the jurist, Bernhard Koerner [de], who later became a prominent Anti-Semite.

In 1894, he was named a Professor and, from 1895 to 1899, was Chairman of the Verein Berliner Kunstler [de] (Artists' Association). In addition to his canvases, he painted altarpieces at the Erlöserkirche in Berlin-Rummelsburg.

He died at home, aged eighty, and is buried at the Luisenstädtischer Friedhof in Berlin-Kreuzberg.