McConnell was president, chairman of the board and principal owner of Avon Allied Products, Inc., and its affiliated companies until his death. He was also treasurer of G.W. Camrick & Co., manufacturers of pharmaceutical supplies in Newark, NJ, and a director of the Holly Hill Fruit Products, Inc., a large orange grove and canning enterprise of Davenport, FL. He was one of the founders of the Suffern National Bank of which he became vice president in 1901, president in 1922 and chairman of the board in 1927. He was again elected chairman of the board and president in 1933 and continued in one or the other office until his death.