Caruthers returned to Carthage in 1823 to practice law. He served as the clerk for the Tennessee House of Representatives for the 1823–1824 term, and worked as editor of the "Tennessee Republican" newsletter. In 1826, he moved to Lebanon, Tennessee, and married Sally Sanders, a niece of Andrew Jackson's wife, Rachel Donelson Jackson. That same year, he was appointed attorney general for the Sixth Judicial District (based in Lebanon) by Governor Sam Houston. He served in this position until 1832. In 1834, he was elected brigadier general in the Tennessee militia. In 1836, he and Alfred O. P. Nicholson published "A Compilation of the Statutes of Tennessee", which remained the state's standard compilation of statutes for over two decades.