Born in Sioux Falls, South Dakota, Schreier earned an Artium Baccalaureus degree from Saint Louis University in 1978 and a Juris Doctor from the Saint Louis University School of Law in 1981.

[1] Schreier worked as a judicial law clerk for South Dakota Supreme Court Justice Francis G. Dunn from 1981 until 1982.

She was elected as Chairwoman of the South Dakota Democratic Party in 1992,[2] and stepped down at the end of the year.

She was recommended by Senator Tom Daschle to serve as United States Attorney for the District of South Dakota in 1993,[4] and was nominated to the position by President Bill Clinton on July 19, 1993.

[8] The United States Senate confirmed Schreier on June 30, 1999, as part of a package of nominees it approved in a 94–4 vote.