[1] Lauritsen was born in Holstebro, Denmark and studied architecture at the Odense Tekniske Skole, graduating in 1911.

In 1926, Lauritsen attended a public lecture by Robert Millikan who, in casual conversation afterwards, invited him to visit Caltech.

Sigrid Lauritsen, who was one of the first female graduates of the University of Southern California medical school, worked in the clinic as a radiologist.

In 1932, he converted one of his X-ray tubes into an accelerator of protons and helium ions and began to study nuclear reactions.

One of his most significant discoveries was to show that protons could be captured by a carbon nucleus, releasing gamma rays.

During the Korean War he was at the front lines just after the Inchon landings observing and evaluating American weaponry for the Defense Department.