His father was the landscape painter, Karl Ferdinand Sohn. After graduating from the, he was drafted for military service, but was rejected for "physical weaknesses". In 1863, he began studying engineering at the Polytechnic School in Karlsruhe. He completed his studies in 1866, but never practiced as an engineer. He returned to Düsseldorf and, shortly before his father's death, he began to study art with him. From 1867 to 1870, he was a student at the Kunstakademie Düsseldorf, where he studied history painting with Karl Müller and figure painting with Julius Roeting. After the outbreak of the Franco-Prussian War, he volunteered for a Hussar regiment, but was placed on reserve. It was then he began private studies with his cousin, Wilhelm Sohn, which eventually determined his choice to be a portrait painter. In 1873, he married, daughter of the painter Alfred Rethel. She would later become a well-known artist in her own right, as well as a popular singer. After the honeymoon, he established a permanent studio in Düsseldorf. He exhibited locally and sold his works in Paris through Goupil & Cie. The following year, he became a lecturer at the Kunstakademie. Within a few years, he was able to afford a larger home and studio. His reputation as a portrait painter spread internationally. From 1882 to 1886, he was summoned to England by Queen Victoria, where he painted her portrait as well as those of Prince Leopold, Princess Beatrice, John Brown, and others. She sat only once, to have him sketch her face, then other court ladies sat for him to fill in the details of clothing. In 1888, he was appointed a juror for the Third International Art Exposition at the Glaspalast in Munich; together with his friends Robert Diez, Fritz Schaper and others. He travelled throughout Italy and France and became an early member of the Deutscher Künstlerbund, participating in their exhibition of 1906. A year after his death, the city of Düsseldorf hosted a memorial exhibition. His sons, Alfred, Otto and Karl all became well-known painters. His brother, Richard Sohn, was also an artist of some note.
