After graduating from Dartmouth, he apprenticed under Salisbury lawyer Thomas W. Thompson. Though unenthusiastic about studying the law, he believed that becoming a lawyer would allow him to "live comfortably" and avoid the bouts of poverty that had afflicted his father. In order to help support his brother Ezekiel's study at Dartmouth, Daniel temporarily resigned from the law office to work as a schoolteacher at Fryeburg Academy in Maine. In 1804, he obtained a position in Boston under the prominent attorney Christopher Gore. Clerking for Gore—who was involved in international, national, and state politics—he learned about many legal and political subjects and met numerous New England politicians. He grew to love Boston, and, in 1805, was admitted to the bar.