US Congressman, Lawyer, Entrepreneur. He was a United States Representative from the State of Pennsylvania. He was born one of two children in Greensburg, Pennsylvania, to William Jack (1752-1821), and his wife Margaret Wilson Jack (1755-1818), on July 29, 1788. He was educated locally and later studied law, was admitted to the bar, and eventually commenced to practicing law. He then relocated to Brookville, Pennsylvania, and engaged in mercantile pursuits, beginning in 1831. He then served as the Division Inspector of Militia for Westmoreland County, Pennsylvania, and Fayette County, Pennsylvania, from 1830 to 1835. He also served as the Sheriff of Brookville, Pennsylvania, in 1833, and was a contractor and builder in the State of Mississippi where he helped in the construction of a canal before returning to his home State of Pennsylvania. After returning to Pennsylvania he bought the Pittsburgher in 1838, a publication formerly named the Allegheny Democrat which was owned first by Wilson F. Stewart and then by Leonard S. Stone who added the Workingmen's Advocate to the name. He then served as a State Court Judge of Jefferson County, Pennsylvania, before becoming involved in politics. He then decided to run for a seat in the United States Congress and was elected to succeed the outgoing United States Representative William Beatty (1787-1851), on March 4, 1841. A Member of the Democratic Party, he then served Pennsylvania's 23rd District (Twenty-Seventh Congress), in the United States House of Representatives from March 4, 1841, to March 3, 1843. Following his term in the United States Congress he was succeeded in office by the incoming United States Representative Charles Manning Reed (1803-1871), on March 4, 1843. After leaving the United States Congress he engaged in agricultural pursuits and other interests. He then returned to Greensburg, Pennsylvania, in 1846. He passed away in Greensburg, Pennsylvania, on February 28, 1852, at the age of 64, and he was buried in Saint Clair Cemetery in Greensburg, Pennsylvania. He was married to Harriet Eason Jack (1809-1879), in Brookville, Pennsylvania, on January 7, 1834, and they had four children together, Sidney Jack (1824-1902), William Jack (1835-1882), Harriet Jack Cowan (1846-1873), and Nancy Wilson Jack Wentling (1850-1902). His wife Harriet later remarried the United States Representative Joseph Henry Kuhns (1800-1883), in about 1853.