Born in Toulouse, France, the sons of modest merchants, he and his brother, Pierre, rose from obscurity to become two of the wealthiest merchants of France. By way of lending money to the government, Antoine was ennobled as the marquis du Châtel, a title he transmitted to his elder son Louis-François. He became a financial counselor to Louis XIV. He invested in the Guinea Company and the Asiento Company, two lucrative overseas franchises. The king eventually offered him a 15‑year trade monopoly in Louisiana.
He married Marguerite Legendre in 1690. They had four children:
- Louis François, marquis du Châtel (1691–1750)
- Marie Anne (1695–1729), who married the comte d'Évreux, Louis Henri de La Tour d'Auvergne, son of Godefroy Maurice de La Tour d'Auvergne and Marie Anne Mancini
- Joseph Antoine, marquis de Thugny (1699–1751)
- Louis Antoine Crozat, baron de Thiers (1699-1770), whose collection of paintings, inherited from his uncle Pierre Crozat, was purchased after his death for the collection of Catherine II of Russia, through Denis Diderot. The paintings now hang in the Hermitage Museum in Saint Petersburg.