It takes more than a visionary eye for style to turn a fashion designer into a blockbuster brand. It takes a combination of right-brain creativity and left-brain execution.

For women's fashion designer Narciso Rodriguez, it has meant hiring left-brain fashion-industry veteran Robert J. Wichser in May. The label tapped him to be chief executive and resident "suit" at the 15-year-old label. Mr. Wichser's mission is to help the Narciso Rodriguez label regain the business mojo that has eluded it in recent years.

The...