George Mifflin Dallas was born in Philadelphia on July 10, 1792, the second of Alexander and Arabella Smith Dallas' six children. Alexander Dallas, a politically well-connected Philadelphia lawyer, served as secretary for the Commonwealth of Pennsylvania and reporter for the opinions of the U.S. Supreme Court and other courts then meeting in that city, which was at the time the nation's capital and leading commercial center. In 1801, as a reward for the elder Dallas' assistance in his presidential election campaign, Thomas Jefferson appointed him U.S. district attorney for the eastern district of Pennsylvania. He remained in that post until 1814, when President James Madison selected him as his treasury secretary. In 1815, Alexander Dallas also served concurrently for a brief period as acting secretary of war. He then resigned the treasury position in 1816 to return to his law practice with the intention of expanding the family's financial resources. However, early the following year, a chronic illness led to his death at the age of fifty-nine, leaving his family without the wealth necessary to support its accustomed style of living.
George Dallas graduated with highest honors from the College of New Jersey at Princeton in 1810. He then studied law and in 1813, at age twenty, was admitted to the Pennsylvania bar. With little taste for legal practice, he sought military service in the War of 1812 but abandoned those plans on the objection of his ever-influential father. He then readily accepted an appointment to serve as private secretary to former treasury secretary and Pennsylvania political figure Albert Gallatin, who was about to embark on a wartime mission to secure the aid of Russia in U.S. peace negotiations with Great Britain. Dallas enjoyed the opportunities that travel to this distant land offered, but after six months orders took him from St. Petersburg to London to probe for diplomatic openings that might bring the war to an end.
In August 1814, as British troops were setting fire to the U.S. Capitol, young Dallas carried a preliminary draft of Britain's peace terms home to Washington and accepted President Madison's appointment as remitter of the treasury, a convenient arrangement at a time when his father was serving as that department's secretary. The light duties of his new post left Dallas plenty of time to pursue his major vocational interest—politics.
In 1816, lonely and lovesick, Dallas left Washington for Philadelphia, where he married Sophia Chew Nicklin, daughter of an old-line Federalist family. (They would eventually have eight children.) His marriage extended his social and political reach but, as his modern biographer reports, "Prestige came without money, a circumstance that was doubly unfortunate because he had developed extravagant tastes as a youth. For this reason he continually lived beyond his means and was constantly in debt, a situation that caused him on more than one occasion to reject otherwise acceptable political posts." At the start of his married life, Dallas achieved a measure of financial stability by accepting a position as counsel to the Second Bank of the United States, an institution his father had helped create while treasury secretary. The 1817 death of Alexander Dallas abruptly ended George's plans for a family law practice. He left the Bank of the United States to become deputy attorney general of Philadelphia, a post he held until 1820.
George Mifflin Dallas cultivated a bearing appropriate to his aristocratic origins. Tall, with soft hazel eyes, an aquiline nose, and sandy hair, he dressed impeccably in the finest clothes his fashionable city could offer, wrote poetry, and, when the occasion warranted, spoke perfectly nuanced French. He developed an oratorical style that capitalized on his sonorous voice and protected him from the barbs of quicker-witted legal adversaries. His biographer explains that, whether "by chance or design, his habit of talking slowly and emphasizing each word created the feeling that he was reasoning his way to a conclusion on the spot. Since he also prepared cases carefully in advance, his apparent groping for the right word—and finding it—reinforced the initial impression that a great mind was at work."
In 1831, the state legislature appointed George Dallas to complete an unexpired term in the U.S. Senate. Although Dallas was a member of the Democratic Party and supported President Andrew Jackson, he was disappointed when the President vetoed a bill to recharter the Second Bank of the United States. Dallas lacked a strong political ambition, and he chose not to run for reelection when his term in the Senate ended in 1833. Still he stayed involved in state politics and served as a state attorney general.
In 1837, President Martin Van Buren appointed Dallas to serve as minister to Russia. Dallas and his family enjoyed their time in Russia although he did not feel his work was very important. They returned home after two years.
During the 1844 election, the Democratic Party turned to Dallas as the vice presidential candidate. He had cordial relations with President James K. Polk although he was never part of the President’s inner circle. As vice president, he felt he should support the President’s positions, and he put the administration ahead of his own political future. When he cast the deciding vote in the Senate for the Walker Tariff, which reduced tariffs and was highly unpopular in Pennsylvania, Dallas essentially ended his future political career. Without home state support, the vice president gave up any hope for a presidential nomination in the 1848 election.
Dallas returned to private life and his legal practice after leaving the vice presidency. President Franklin Pierce appointed him minister of Great Britain, and he served from 1856 to 1861. He died on December 31, 1864. The city and county of Dallas, Texas, were named after him.