After completing an internship at the PHS Marine Hospital in New Orleans, Sebrell was assigned to the Hygienic Laboratory (as the National Institutes of Health was then known) in Washington, D.C.[2] A leading international authority on nutrition, Sebrell first recognized and described the dietary deficiency disease, ariboflavinosis, and made significant contributions to knowledge of dietary needs and deficiencies.

He began his research career under Dr. Joseph Goldberger, who demonstrated that pellagra is a deficiency disease.

This program aided food production and the maintenance of civilian health during the war years.

[3] Sebrell helped to formulate the first international standards of nutrition for the League of Nations and pioneered the growing acceptance of scientific nutrition as a regular function of modern state and local health departments.

[6] On September 29, 1992, Sebrell died from cancer at his home town in Pompano Beach, Florida.