Ambitious, he used his time to study the intricacies of stock trading and because of personnel shortages created by so many young French men serving in the military in World War I, he was able to get a job with Baur & Fils, a small Paris bank.

As well, from 1927, representing Lazard along with Paul Frantzen and Raymond Philippe, André Meyer was elected to Board of Directors of the failing automobile giant Citroën.

André Meyer, called "the most creative financial genius of our time in the investment banking world" by David Rockefeller, became one of the most important people in American business with an influence that extended around the globe.

An avid collector of art objects, Meyer's eclectic assemblages included paintings by Claude Monet, Marc Chagall, and Pablo Picasso, sculptures, Louis XIV furniture, and original music scores.

His collection of music scores began with works by Georg Muffat and Jean-Philippe Rameau, and expanded to include scores by Georg Frideric Handel, François Couperin, Antonio Vivaldi, Vincent Lübeck, Jean-Baptiste Lully, Christoph Willibald Gluck, a sketchleaf of Ludwig van Beethoven once owned by Frédéric Chopin, Igor Stravinsky, Arnold Schoenberg, Johann Kuhnau, Domenico Scarlatti, Carl Philipp Emanuel Bach, Johann Christian Bach, and Carl Friedrich Abel.

When his collection was sold by Sotheby's on 16 and 17 October 2012, they noted that the collection contained beautifully bound 16th and 17th century scores by composers whose manuscripts rarely come up at auction anymore including Orlande de Lassus, Claudio Monteverdi, Jacques Arcadelt, Cristóbal de Morales, Luca Marenzio, Giovanni Pierluigi da Palestrina, Marco da Gagliano, Girolamo Frescobaldi, Jacopo Peri & Ottavio Rinuccini, and Antonio Cesti, among others.