His first major assignment was when his friend Mickey Deans asked him to cover his wedding to Judy Garland, which marked the beginning of Warren's work as a professional photographer.
Primul său contract important l-a obținut de la prietenul său, Mickey Deans, care i-a cerut să facă fotografii la nunta lui cu Judy Garland, ceea ce a marcat începutul activității lui Warren ca fotograf profesionist.