Judge Tiefenthaler graduated from the University of South Dakota with a Bachelor of Science Degree in Political Science and Criminal Justice in 1991 and from the University of South Dakota Law School in 1994. During law school in 1994, he served a clinical internship in the Woodbury County Attorney’s office. After graduation, Judge Tiefenthaler started as an associate with a Sioux City law firm in July 1994, and was partner and eventual shareholder in the firm from approximately 1996-1999. In July 1999, Judge Tiefenthaler opened his own law office named Tiefenthaler Law Office, P.C. in Sioux City. In private practice, he handled primarily civil tort, workers’ compensation, criminal defense, juvenile law, and family law matters.
He remained a solo practitioner until his appointment as a District Court Judge in July 2022. He was also a member of The Iowa Bar Association, the Nebraska Bar Association, the South Dakota Bar Association, the Woodbury County Bar Association, the American Association for Justice, the National Association of Criminal Defense Lawyers, the National College for DUI Defense, and the South Dakota Association of Criminal Defense Lawyers.