On November 17, 1913, Vennesland was born in Kristiansand, Norway to Sigrid Kristine, a teacher, and Gunnuf Olaf, a timber merchant.

For her first years, Vennesland grew up with her mother and twin sister in Norway, while her father immigrated to the United States.

[4] After receiving her degrees, Vennesland worked at the University of Chicago for a year as a biochemist assistant before leaving for Harvard Medical School in 1939.

[10] During her tenure at Chicago, Vennesland also worked for the Office of Scientific Research and Development, United States Public Health Service and National Science Foundation.

[1] Upon ending her career with Chicago, Vennesland emigrated to Germany to become the director for the Max Planck Institute for Cell Biology in 1968.