Born November 7, 1788, in Washington County, Pennsylvania, near Wheeling, Virginia. After passing the bar exam, he practiced law in Wheeling, Virginia. He was a member of the Virginia House of Delegates from 1817 to 1819, 1823 to 1827, 1832, and 1833. He also served in the U.S. House of Representatives from 1827 to 1829. Mr. Leffler moved to what became Des Moines County, Iowa Territory, in 1835. He represented Des Moines County in the House of Representatives of the Fourth Legislative Assembly of the Iowa Territory from December 1841 to December 1842. He married his wife, Susannah, in Burlington, Iowa, on October 28, 1842. Mr. Leffler was appointed United States marshal by John Tyler from 1843 to 1845. He then practiced law, but was later appointed receiver of public moneys by President Millard Fillmore from 1852 to 1853. He died March 8, 1866 in Chariton, Iowa.