His most famous works include Rita Hayworth's black satin strapless dress from Gilda (1946), Marlene Dietrich's celebrated beaded souffle stagewear for her cabaret world tours, as well as the sheer, sparkling gown that Marilyn Monroe wore when she sang "Happy Birthday, Mr. President" to John F. Kennedy in 1962.

[citation needed] Louis had originally designed a version of the dress for Marlene Dietrich, who wore it in her concert shows.

Some of his clients included Ginger Rogers, Irene Dunne, Lana Turner, Vivien Leigh, Joan Crawford, Julie Andrews, Katharine Hepburn, and Judy Garland.

Some of his film credits included, A Star Is Born, Ship of Fools, From Here to Eternity, Thoroughly Modern Millie, and he won an Oscar for his designs in The Solid Gold Cadillac in 1956.

The Carnegie suit was one of the first fashions to become very well-liked as an American name design, and its fitted blazer and long pencil skirt was worn by several actresses and society women at the time.