George Sweeney was born on November 1, 1796 near Gettysburg, Pennsylvania. He entered Dickinson College in Carlisle, twenty five miles to the north, and graduated with the class of 1815. Following his graduation, he studied law in Gettysburg and was admitted to the bar there in 1820.
For ten years Sweeney practiced law in Gettysburg and then moved west to Bucyrus in Crawford County, Ohio in 1830. He was named as the prosecutor of Crawford in 1837 and then was elected in the fall of 1838 as a Democrat to the Twenty-sixth Congress from his district, the 14th of Ohio. Although Sweeney was re-elected to the Twenty-seventh Congress in 1840, he was not a candidate in 1842. He moved for a time to Geneseo, Illinois to practice law in 1853, but returned to Bucyrus in 1856. Sweeney was once again elected as district attorney for Crawford County before he retired.
Sweeney gave up his profession in later years to concentrate on the literary and scientific pursuits that had interested him his whole life. On October 10, 1877, George Sweeney died in Bucyrus, Ohio and was buried in the Oakwood Cemetery there. He was eighty years old.