During World War II Holley spent two years working under Professor Vincent du Vigneaud at Cornell University Medical College, where he was involved in the first chemical synthesis of penicillin.
Tokom Drugog svetskog rata Holi je proveo dve godine radići pod nadzorom profesora Vinsent du Vinoa na Medicinskom koledžu Kornel univerziteta, gde je učestvovao u prvoj hemijskoj sintezi penicilina.