Christian Krohg completed his degree as a lawyer already at age 21. After this he started his education to become a painter. One of his teachers was Hans Gude in Karlsruhe and Berlin. Later he had several short stays in Skagen, where some of his best pictures were created; including "The port bit".
Krohg believed that painters should get their scenes from contemporary life. He saw art as a social matter, not a private matter. In his paintings he often presented people from lower social classes and contributed in this way to increased attention to the differences in people's living conditions. This applies for example in the painting "The struggle for existence". He was also a highly regarded portrait painter and painted a famous picture of Johan Sverdrup.
Krogh was an independent person with well informed opinions. He did not follow the herd, but was a leading figure in the radical Christiania Bohemians.
In 1886 he released "Albertine" a novel about a working girl who ends as a prostitute. The book was confiscated shortly after its publication because of its content.
For a period, everything went downhill and his production stopped. He started to work as a journalist and wrote for the Norwegian newspaper Verdens Gang for 20 years. This was a different newspaper than the current VG, where he made portrait interviews and even illustrated them with drawings. Later he started to paint again.
Krohg was also the director of the newly established Academy of Art in Christiania and played a significant role in the building of the House of Artists.
Christian Krohg was married to Oda Krohg.