During Gritzner's third year of law school, he worked as a full-time law clerk to then-United States Magistrate Judge Ronald Longstaff of the United States District Court for the Southern District of Iowa.
[1][2] From 1979 to 1981, Gritzner was an associate of the Waterloo, law firm Mosier, Thomas, Beatty, Dutton, Braun, and Staack.
[3] From 1981 to 1982, he worked at Humphrey, Haas and Gritzner, a new law firm in Des Moines, before leaving after a dispute about the propriety of attorney advertising under ethical rules.
[1] One of Gritzner's specialties was litigation over catastrophic fires and explosions, in which he maintained a nationwide practice.
[4] Gritzner was also particularly noted for his expertise in legal ethics issues and was the primary prosecutor for the Committee on Professional Ethics and Conduct of the Iowa State Bar Association and the Client Security and Attorney Disciplinary Commission of the Iowa Supreme Court.