One of the most prominent and influential citizens of his adopted home city in the 19th Century. During his career, he was a director in the Philadelphia, Wilmington and Baltimore Railroad for 37 years, which built its southern terminus in 1849–1850, east of the harbor "basin" (today's modern "Inner Harbor") at President and Fleet Streets of the President Street Station, (which is today the Baltimore Civil War Museum, with its landmark architectural design, the oldest big city train depot left in America and a historic site in the American Civil War for the infamous "Pratt Street Riots" with the "First Bloodshed of the Civil War" of April 19, 1861). Kelso was also the president of the Baltimore Equitable Fire Insurance Company, one of the oldest such fire insurers in the nation. vice president and director in the First National Bank of Baltimore, principal Director and principal stockholder in the Baltimore Steam Packet Company (locally famous as "The Old Bay Line") and the Seaboard and Roanoke Railroad Company, president of the Preachers' Aid Society of the Methodist Episcopal Church, and member and later President of the Board of Trustees of the Male Free School of Baltimore, organized 1802 under the direction of the trustees of the Methodist Episcopal Churches of Baltimore in the school room at the old Light Street Methodist Episcopal Church (between Baltimore and German (later Redwood) Streets, second site of the former historic Lovely Lane Meeting House or Chapel, (off German (now Redwood) Street, east of South Calvert Street), then known as the First Methodist Episcopal Church when constructing its 1884 "Centennial Monument of American Methodism" building at St. Paul and 23rd Streets in the Peabody Heights, now Charles Village neighborhood.