[10] Polk's roommate was William Dunn Moseley, who became the first Governor of Florida. Polk joined the Dialectic Society where he took part in debates, became its president, and learned the art of oratory.[11] In one address, he warned that some American leaders were flirting with monarchical ideals, singling out Alexander Hamilton, a foe of Jefferson.[12] Polk graduated with honors in May 1818.[11]
After graduation, Polk returned to Nashville, Tennessee to study law under renowned trial attorney Felix Grundy,[13] who became his first mentor. On September 20, 1819, he was elected clerk of the Tennessee State Senate, which then sat in Murfreesboro and to which Grundy had been elected.[14] He was re-elected clerk in 1821 without opposition, and continued to serve until 1822. In June 1820, he was admitted to the Tennessee bar, and his first case was to defend his father against a public fighting charge; he secured his release for a one-dollar fine.[14] He opened an office in Maury County[2] and was successful as a lawyer, due largely to the many cases arising from the Panic of 1819, a severe depression.[15] His law practice subsidized his political career.