Kärner also wrote numerous novels, plays, works of literary criticism, and scientific literature and historical treatises.
He translated works from German and Russian, most notably the poems of Heinrich Heine into Estonian in 1934.
He had one brother, Johannes, and five sisters: Anna Marie, Emilie, Pauline, Ida and Alma and two half-brothers Aleksander and August.
During the German occupation of Estonia during World War II Kärner lived in the Soviet Union.
With the re-incorporation of Estonia into the Soviet Union in 1944, he returned to his homeland and worked in publishing as an editor at various newspapers and magazines.