Richard P. Tieszen is the managing member of Tieszen Law Office, Prof. LLC, in Pierre, South Dakota. He is a 1975 graduate of Black Hills State University obtaining his juris doctorate degree, cum laude, from the University of South Dakota Law School in 1979. Tieszen was recognized as a Thomas Sterling Honor Society Award graduate before being admitted to practice in South Dakota in 1979. Richard began his career as a law clerk for the Sixth Judicial Circuit Court in Pierre, South Dakota, and after one year as a law clerk, Richard began his private practice career as a trial lawyer, primarily in the area of criminal defense and plaintiff trial work. In 1986, Tieszen left private practice to serve in the capacity as the South Dakota Chief Deputy Attorney General managing a staff of 140 attorneys and staff under then Attorney General Roger Tellinghuisen. In December 1989, Tieszen formed the firm of Tieszen Law Office. Since that time, the firm has expanded to four (4) attorneys and one paralegal in addition to several support staff. In addition to the state courts of South Dakota, Tieszen is admitted to practice before the United States District Court for the District of South Dakota, the United States Circuit Court of Appeals for the Eighth Circuit, and the United States Supreme Court.

Tieszen has received the highest possible peer review rating in legal ability and ethical standards from the Martindale-Hubbell Peer Review:

Richard's law practice encompasses insurance law defense, gaming law, administrative law, education law, environmental law, and business/corporate law resulting in a practice which includes considerable trial work. The firm represents a number of municipalities and school districts throughout the state of South Dakota.

Tieszen formerly served as counsel to the South Dakota Petroleum Release Compensation Fund for 9 years doing environmental law. Tieszen currently serves as counsel for the Associated School Boards of South Dakota Protective Trust and many school districts throughout the state. Since 1984, Tieszen has represented State Farm Insurance Companies as its South Dakota state retained counsel.

Tieszen also lobbies for State Farm and several other organizations, including the South Dakota Sheriff's Association, Waste Management of South Dakota, Inc., Associated School Boards of South Dakota, Lake Area Technical Institute, Mitchell Technical Institute, Southeast Technical Institute, Western Dakota Technical Institute, and American Express.

Tieszen served as Chairperson of the Juvenile Justice Advisory Commission after appointment by deceased former Governor George Michelson and now manages an active lobby practice in the State Legislative arena.

He and his wife, Kay Thompson-Tieszen, raised son Ryker who is now in Law School at the University of South Dakota and son Kyler who is an electrician in Sioux Falls, South Dakota.