John Pershing Byrnes Practice Areas Category: Business Law ProfileReviewsJohn Pershing Byrnes completed law school at University of South Carolina and has been practicing law since 11/13/1989. John Pershing Byrnes is located in Saint Simons Island, GA Leave a Review Cancel reply Your email address will not be published.Review text Select a rating Overall Name Email Website Save my name, email, and website in this browser for the next time I comment.