A Scots-Irish immigrant, Mr. Campbell served as a messenger at General John Fremont´s headquarters at the age of 14. After the Civil War, Mr. Campbell worked as a surveyor for the Atlantic & Pacific Railroad and began buying land ahead of the tracks. With his profits, he invested in railroad bonds, then in St. Louis street railways. He became the primary stockholder of the Mercantile Trust.

One of Mr. Campbell’s ventures, the Welsbach Company, gained the contract for most of the city´s street lighting in 1899. He was also president and later chairman of the North American Company, a utilities holding combine that controlled the Laclede Gas and Union Electric companies. By 1900 he was a multi-millionaire with a mansion at #2 Westmoreland Place. He is buried at Calvary Cemetery.