Karl Emil Georg Johnson was born in Hedvig Eleonora parish in Stockholm, Sweden.
He was the son of Frans Emil Jonsson (1861–1917) and Jenny Augusta Jonsdotter (1863–1906).
In 1916, he appeared as an actor under the direction of   Hjalmar Selander at the Nya Teatern in Gothenburg.
In 1919, he debuted as a couplet singer at the cabaret Fenixpalatset in Stockholm  as successor to Ernst Rolf (1891–1932).
For many years, he was an actor in various traveling theater companies.

Through most of his career, he wrote songs and couplets as well as a large number of sketches, dialogues and monologues for performance on the stages of Stockholm and Gothenburg.
Many of Karl Gerhard’s plays and songs were politically to the left, and during the 1930s and World War II, they contained clear anti-fascist statements.
He composed and sang a number of couplet text that sharply criticized the Swedish government's apathy towards Nazi Germany.

He was married three times: to actresses  Mary Johnson  (1913 to 1920), Valborg Geyron (1922 to 1930) and Brita Werner (1930 to 1936).

He was the father of actor Per Gerhard (1924–2011).
Karl Emil Georg Johnson was born in Hedvig Eleonora parish in Stockholm, Sweden. He was the son of Frans Emil Jonsson (1861–1917) and Jenny Augusta Jonsdotter (1863–1906). In 1916, he appeared as an actor under the direction of   Hjalmar Selander at the Nya Teatern in Gothenburg. In 1919, he debuted as a couplet singer at the cabaret Fenixpalatset in Stockholm  as successor to Ernst Rolf (1891–1932). For many years, he was an actor in various traveling theater companies. 
Through most of his career, he wrote songs and couplets as well as a large number of sketches, dialogues and monologues for performance on the stages of Stockholm and Gothenburg. Many of Karl Gerhard’s plays and songs were politically to the left, and during the 1930s and World War II, they contained clear anti-fascist statements. He composed and sang a number of couplet text that sharply criticized the Swedish government's apathy towards Nazi Germany.
He was married three times: to actresses  Mary Johnson  (1913 to 1920), Valborg Geyron (1922 to 1930) and Brita Werner (1930 to 1936).
He was the father of actor Per Gerhard (1924–2011).
Karl Gerhard