Karl M. Bengtson was born in Steneby, Dalsland, and was an architect and builder.
After studying at Chalmers University of Technology in 1896-1906, Bengtson continued his studies at Kunstgewerbeschule and the Art Academuy in Munich, where he studied with Carl Milles, amongst others. After a period of travel and architectural studies in Italy, he returned to Munich and started as a theater architect with Professor Martin Dülfer, who used to be his teacher. Later in life he moved back to Sweden, and ran his business from Gothenburg.