He was later was connected with a magazine publishing company in Pittsburgh and with leading newspapers in New Orleans, Louisiana. He was engaged in steamboating on the lower Mississippi River from 1841 to 1847 and in gold mining in California in 1851. He aided in the building of the Cambria Iron Works in Johnstown, Pennsylvania, in 1853, and was employed by that company until 1861, when he resigned. Campbell was a delegate to the first Republican National Convention at Philadelphia in 1856.