Born in Nashville, Tennessee, Jim traveled worldwide as an "Army brat" until graduating from high school in Japan. While attending Mississippi College in Clinton, Mississippi, where he received his Bachelors of Arts and Masters of Arts degrees, he decided to make Mississippi his home. From 1969 through 1971, Jim served in the U.S. Army in Vietnam as a First Lieutenant with the 101st Airborne Division. After his military service, he earned his Juris Doctor degree in 1977 from the University of Mississippi.

Jim established Shannon Law Firm in Hazlehurst, Mississippi and is committed to legal and community involvement in Hazlehurst, Mississippi, where he serves as Municipal Court Judge and attorney for the Copiah County Board of Supervisors. He is licensed to practice in all state and federal courts in Mississippi as well as the 5th Circuit Court of Appeals and the United States Supreme Court. He has participated in cases in Mississippi, Texas, Ohio, Michigan, Minnesota, Pennsylvania, New York, Florida, and many other states. Also he has participated in hundreds of cases in the Virgin Islands and the country of Venezuela.

Jim was recognized in 2001 as one of America's Top 10 lawyers, by Lawyers Weekly USA. The legal publication highlighted Shannon as one who "stood out from the crowd" among the country's million lawyers who make a difference. The national publication for legal professionals also spotlighted Shannon for his trial work on the first jury verdict involving the drug Propulsid.

In 2001 alone, two of Jim's cases were highlighted in The National Law Journal in their "Largest Verdicts" listing and ranked tenth in the country in trial verdicts. In addition to his active trial practice, Jim Shannon speaks at national tort litigation seminars. He is co-counsel with law firms nationally and internationally in high profile tort litigation. Since 1999, Jim has been a Million Dollar Advocate.