He graduated from Phillips High School in 1957 and earned his bachelor's degree in English and philosophy from Birmingham-Southern College in 1962. He went on to graduate with honors from the Cumberland School of Law in 1967 and was admitted to the Alabama State Bar that same year Isom accepted a position with the firm of Berkowitz, Lefkovits, Vann, Patrick & Smith and rose to become chair of its real estate practice group. That firm was acquired by Memphis, Tennessee-based Baker Donelson in 2003.
Isom has served on the Norton Board of Advisors at Birmingham-Southern as well as on the boards of the Norwood Resource Center, the Legal Aid Society of Birmingham, the Birmingham Arts Journal, the Alabama Writers' Forum, and Four Spirits Inc..
Isom's 2013 memoir The Newspaper Boy recounts his youth and education against the backdrop of the Cold War and Birmingham's Civil Rights Movement. Isom and his wife, Martha, moved back to Norwood while he was working on that book.