Before coming to Hollywood, he worked in New York for fashion entrepreneurHattie Carnegie, where the clientele included Joan Cohn, the wife of Columbia Pictures studio chief Harry Cohn. He worked as head designer for Columbia Pictures from 1944 to 1960. His most famous works include Rita Hayworth's black satin strapless dress from Gilda, 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. The dress was so tight that he is believed to have actually sewn it while Monroe was wearing it. The idea of dresses being a nude color, with crystals coating it, stunned audiences. It gave the members of the audience the illusion that Monroe was nude, except for discretely placed rhinestones covering them head to toe. Louis had originally designed a version of the dress for Marlene Dietrich, who wore it in her concert shows. An impressed Monroe asked Dietrich about it, who told her how the dress's illusion worked, and sent her to Louis to design a similar dress for her Kennedy appearance. While Dietrich had been seen wearing her version before Monroe, the press coverage surrounding Monroe's appearance at Madison Square Garden in her style of gown swept the globe. This robe became—besides the white one from "The Seven Year Itch"—Marilyn Monroe's most famous robe, selling at auction in 2016 for 4.8 million dollars. In 1993, four years after the death of his second wife, Louis married former client Loretta Young; they remained married until his death in 1997. He had designed Young's wardrobe for her TV program The Loretta Young Show, an anthology show noted for Young's show-opening and closing scenes that had viewers tuning in especially to view her high-fashion outfit for that week. Young was known as the best-dressed actress in America at that time. For over forty years, Louis designed clothes for almost every star in Hollywood. Around sixty of his designs appeared in movies, and he was eventually nominated for 13 Academy Awards. 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. In 1937, a year after Louis immigrated to the United States, he designed a suit that became an icon in the fashion world. The Carnegie suit was one of the first fashions to become very well-liked as an American name design. The fitted blazer and long pencil skirt was worn by several actresses and society women at the time. The Duchess of Windsor became one of his most famous clients, as well as the First Lady Nancy Reagan in the 1980s.
Rita Hayworth in Tonight and Every Night, 1945, Gilda, 1946, Down To Earth, 1947, The Lady from Shanghai, 1948, The Loves of Carmen, 1948, Affair in Trinidad, 1952, Miss Sadie Thompson and Salome, 1953
Irene Dunne in Together Again, 1944
Claudette Colbert in Tomorrow is Forever 1946
Judy Holliday in Born Yesterday, 1950 and The Solid Gold Cadillac, 1956
