Lanvin made clothes for her daughter, Marie-Blanche de Polignac, which began to attract the attention of a number of wealthy people, who requested copies for their own children. Soon, Lanvin was making dresses for their mothers, and some of the most famous names in Europe were included in the clientele of her new boutique on the rue du Faubourg Saint-Honoré, Paris. In 1909, Lanvin joined the Syndicat de la Couture, which marked her formal status as a couturière. The Lanvin logo was inspired by a photograph taken for Jeanne Lanvin as she attended a ball with her daughter wearing matching outfits in 1907.

From 1923, the Lanvin empire included a dye factory in Nanterre. In the 1920s, Lanvin opened shops devoted to home decor, menswear, furs and lingerie, but her most significant expansion was the creation of Lanvin Parfums SA in 1924. "My Sin", an animalic-aldehyde based on heliotrope, was introduced in 1925, and is widely considered a unique fragrance. It would be followed by her signature fragrance, Arpège, in 1927, said to have been inspired by the sound of her daughter's practising her scales on the piano.

Jeanne Lanvin was one of the most influential designers of the 1920s and 1930s. Her use of intricate trimmings, virtuoso embroideries and beaded decorations in clear, light, floral colors became a Lanvin trademark.