After the war he opened his own fashion house in Paris, and soon added branches in other French cities as well as London. He was known for clothing that was perfectly tailored and very wearable. During the 1930s he designed elegant evening dresses with matching coats.

Molyneux returned to London during WWII, where he worked designing Utility clothing - garments that met the strict fabric conservation laws that were in place during the war.

He returned to Paris after the war and reopened his couture house. In 1950, Molyneux created a new twist on the American custon of importing French clothing and making copies.   In the spring of that year, he bought 50 designs from ten American sportswear designers, including Tina Leser, Claire McCardell and Carolyn Schnurer, with the intentions of reproducing them in France.  But increasingly poor health caused him to sell his business to his former assistant Jacques Griffe later that year.

He retired to the West Indies, but later opened Studio Molyneux, a high quality ready-to-wear line, in 1964. He retired for good in 1969, however Studio Molyneux continued under the direction of John Tullis untill 1977, when it closed.

Label note:  Adaptation labels were used not by the designer, but by US firms that were making fashions that were adapted from the designer's work.  Many firms did adaptations, and an adaptation might be a faithful reproduction of the original, or it might be very loosely based on the designer's work.