Born in La Rochelle, Laroche began in millinery and worked from 1949 for Jean Dessès before founding his own high-fashion atelier in Paris in the mid-1950s. His clothes featured plunging neck and back lines, and for the American market he was one of the first to create separates. He moved to a townhouse on Avenue Montaigne in 1961, opened a boutique and showed his first ready-to-wear, then launched menswear in 1966.
He cited Dior, Balenciaga, Jacques Fath and Balmain as his main influences, and introduced the fragrance Fidji in 1966, later followed by Drakkar Noir. Hilary Swank wore a navy Guy Laroche gown to accept her 2005 Academy Award; Marcel Marongiu became artistic director in 2007.