Karl Oscar Isakson (16 January 1878, Stockholm – 19 February 1922) was a Swedish painter who spent much of his professional life in Denmark where he is considered to be one of the fathers of Modernism. He had close associations with the Bornholm school of painters and made many paintings of Christiansø. He is cited as an artist who "sought to give their Biblical works a modern social and political context."

Isakson was brought up in difficult circumstances in Stockholm. His father, blacksmith Karl Frederik, died when he was only eight months old, leaving his mother, Mathilda, to raise him and his sister Esther by running a laundry. At school he did so well he was known as the little professor. At home, in order to escape from the fam...