By making that task easier for their stylish customers, Julian O’hayon, 28, and Thomas Johnston, 20, have grown their luxury streetwear brand Blvck Paris to $1 million in annual revenue.

Blvck Paris is known for its all-black clothing, accessories and leather goods for men and women. Blvck Paris will be opening its first U.S. location in New York City on Sept. 7. The lifestyle ...