McLane's father, Allan, was a veteran of the American Revolutionary War, appointed by George Washington in 1797 to the lucrative federal position of Customs collector for the Port of Wilmington. As a well-known and fervently loyal Federalist, he received the strong backing of James A. Bayard, enabling him to keep his appointment despite the election of a political opponent, Thomas Jefferson. Allan McLane retained the position for over 30 years, under presidents of both parties, until his death during the administration of Andrew Jackson. Much of his income came from the seizure of contraband. Louis McLane inherited much of this wealth, along with legal issues that lasted well beyond the death of his father.