[2] In November 1929, Main Rousseau Bocher merged his own name, in honor of his favorite couturieres, Augustabernard and Louiseboulanger, and established his own fashion house, incorporated as "Mainbocher Couture" at 12 Avenue George-V in Paris.

[4] His subtle and timeless style won Mainbocher an exclusive clientele, which included fashion editors Carmel Snow, Bettina Ballard, Diana Vreeland; aristocrats Princess Karam of Kapurthala, Elsie de Wolfe, Lady Castlerosse, the Vicomtesse de Noailles, Baroness Eugène de Rothschild; pianist Dame Myra Hess; socialites Millicent Rogers, Daisy Fellowes, Mrs. Cole Porter, Syrie Maugham, and Hollywood stars Mary Pickford, Constance Bennett, Kay Francis, Claudette Colbert, Irene Dunne, Loretta Young, Miriam Hopkins, and Helen Hayes.

"[11] Mainbocher's corseted waist, defined bosom, and back draping was an abrupt shift in silhouette and introduced the Victorian motifs that were to pervade the forties.

In 1940, he relocated his business to New York on 57th Street next to Tiffany's and established "Mainbocher Inc." He recreated his Paris salons exactly as they were and stayed to true to haute couture traditions.

[4] During the war, Mainbocher designed a series of uniforms for both military and civilian organizations, applying his principles of functionality and utility while retaining the sophisticated elegance of his namesake label.

In 1950, he designed a one of a kind evening dress uniform for Colonel Katherine Amelia Towle, who was then Director of Women Marines (USMCR).

In New York, Mainbocher continued to dress generations of women like debutante Brenda Frazier, Doris Duke, Adele Astaire, Elizabeth Parke Firestone, Gloria Vanderbilt, Lila Wallace, Bunny Mellon, Babe Paley, Princess Maria Cristina de Bourbon, Kathryn Miller, and C. Z.

[citation needed] In 2002, Mainbocher was honored with a bronze plaque on New York City's Fashion Walk of Fame in the legendary Garment District.