Shannon was the son of Lester Norman and Kate Little Shannon of Birmingham. He attended the McCallie School in Chattanooga, Tennessee and began college at Princeton University before going into service with the U. S. Navy in 1944. After the end of World War II he enrolled at Birmingham-Southern College to complete his degree and took a job at Birmingham Trust National Bank.
In 1951 Shannon, a Naval reservist, was called back to active duty in the Korean War. He returned to Birmingham in October 1952 and was promoted to Vice President at BTNB shortly afterward. In 1956 he joined Berney Perry & Company as an investment banker and began developing residential lots in Mountain Brook on his own. In 1961 he was made a partner in Pierce Garrison Wolborn, then left in 1964 to open his own firm, J. H. Shannon & Co..
Shannon was instrumental in lobbying for public financing for hospital construction. His firm was involved in the financing of Carraway Methodist Medical Center, Bessemer Carraway Medical Center, Baptist Medical Center, St Vincent's Hospital and Children's Hospital.
In 1984 Shannon was named president, CEO and chairman of the Alabama Federal Savings & Loan Association, which reorganized as Secor Bank and was later acquired by Regions Bank. Shannon retired from Secor in 1991.
In addition to his business leadership, Shannon served on the boards of Indian Springs School, Lakeshore Rehabilitation Hospital and Children's Hospital. He also supported UAB, the Birmingham Museum of Art and United Way of Central Alabama. He was a member of the Mountain Brook Club, the Redstone Club, and St Mary's-on-the-Highlands Episcopal Church.
Shannon died in 2011. He was survived by his wife, Elizabeth; seven children, and four grandchildren.
- "Jack Herbert Shannon" obituary (February 16, 2011) Birmingham News