Floyd E. Thompson established a robust legal career marked by significant contributions to criminal law and the legal profession. He began his career post-graduation, working on the family farm and as a teacher before being admitted to the bar of Tennessee and Illinois. Thompson founded a law practice in East Moline, Illinois, and became the publisher of the East Moline Herald. He served as State's Attorney for Rock Island County and later as a justice on the Supreme Court of Illinois. Thompson also chaired the American Bar Association's Section of Criminal Law and was a charter member of the American Law Institute. His career included high-profile cases, such as defending Floyd Cerf in the prosecution of Preston Tucker and Tucker Corporation executives.

Floyd E. Thompson's political identity is marked by an intriguing blend of stringent legalism and calculated pragmatism in economic matters. His advocacy for stringent legal measures against financial fraud contrasts with his defense of a controversial figure in the Tucker Corporation case, revealing a nuanced approach to corporate accountability. Thompson's career in criminal law, including high-profile prosecutions and defenses, underscores a deep-seated commitment to justice, yet his strategic legal maneuvers suggest a highly localized, interest-driven approach.