Mahlon Dickerson was born in 1770 in Hanover Neck, New Jersey. He graduated from the College of New Jersey (now Princeton University) in 1789, studied the law, and became a licensed attorney in 1793.

Though his parents had made Dickerson wealthy by leaving him all their land and business interests, he served as a private in the New Jersey Detached Militia, helping to quell the Whiskey Rebellion, and then practiced law in Philadelphia. In 1802, he was elected to the Philadelphia Common Council and shortly thereafter appointed by Pennsylvania's governor as a state commissioner for Bankruptcy. He would ultimately become adjutant general of Pennsylvania. Dickerson returned to New Jersey in 1810 and a year later was elected to the New Jersey state assembly. He served for three years before becoming law reporter for the New Jersey state supreme court and then, in 1814, a member of the state supreme court. After Governor Pennington resigned in 1815, Dickerson was tapped to replace him, remaining in Trenton from 1815 to 1817, when he was elected to the United State Senate.

Dickerson served in Congress from 1817 to 1829, when he resigned. However, he was immediately elected to fill the second Senate seat that had been vacated, and so he again sat in the Senate until 1833, when he resigned once more. A year later, President Jackson tapped Dickerson to become his minister to Russia. Dickerson agreed but was surprised to find, after arriving in Washington, D.C., that Jackson had changed his mind and decided to make Dickerson his secretary of the Navy. Dickerson agreed to the change and served as secretary for both Presidents Jackson and Van Buren before he resigned in 1838. In 1840, Mahlon Dickerson became a district court judge in New Jersey and served as a delegate to the state constitutional convention in 1844. He died in 1853.