After working under his father, and at Metz, Adam arrived in Paris in 1719. He won the premier prix at the Académie in 1723, then left for Rome with Bouchardon. Patronized there by Cardinal de Polignac and Pope Clement XII, he was joined by Nicolas Sébastien in 1726 and later by François Gérard. Adam won the competition for designing the Fontana di Trevi, but failed to gain the commission.

In 1733, Adam returned to Paris where his Neptune Calming the Waves (Louvre, Paris) was completed in 1737. The statue's debt to Bernini was self-evident, but its dramatic flamboyance and vitality compensate for its lack of originality. This immensely decorative treatment also proved ideal for the central group of Neptune and Amphitrite, executed in lead by the family workshop for the Basin de Neptune at Versailles. Completed in 1740, this exuberant group was a great success, but the same principles as applied to the bust of Louis XV as Apollo (before 1741; terracotta; Victoria and Albert Museum, London) result in empty grandiloquence. Nicolas Sébastien's Monument to Queen Catharina Opalinska (set up 1749, Notre-Dame de Bon Secours, Nancy) is a finer, less ostentatious work.