Carothers, the son of a teacher, was born in Burlington, Iowa, and gained a BS degree from Tarkio College, Missouri (1920), after working his way through college. He gained his PhD in 1924 from the University of Illinois and was an instructor in chemistry at Illinois and Harvard before joining the Du Pont company at Wilmington, Delaware, as head of organic chemistry research in 1928.

Carother's early work was in the application of electronic theory to organic chemistry but at du Pont he worked on polymerization. His first great success was the production of the synthetic rubber, neoprene (1931). Working with acetylenes he discovered that the action of hydrochloric acid on monovinylacetylene produced 2-chloro-buta-1,3-diene (chloroprene), which polymerized very readily to give a polymer that was superior in some respects to natural rubber.

In a systematic search for synthetic analogs of silk and cellulose he prepared many condensation polymers, especially polyesters and polyethers. In 1935 one polyamide, produced by condensation of adipic acid and hexamethylenediamine, proved outstanding in its properties and came into full-scale production in 1940 as Nylon 66. But Carothers did not live to see the results of his achievements; despite his brilliant successes he suffered from fits of depression and took his own life at the age of 41.