Rush received her undergraduate degree from Purdue University in 1980 and her J.D. from the Indiana University Maurer School of Law in 1983. Rush worked at a law firm for 15 years before serving as a Tippecanoe County Superior Court judge. She was elected to that position three times. In 2012, Gov. Daniels appointed her to the state supreme court. Voters retained her in 2014. In August of that year, the judicial nominating commission named her chief justice, to which position the commission reappointed Rush in 2019. Rush co-chaired the National Judicial Opioid Task Force. As of July 2021, she was vice president of the Conference of Chief Justices Board of Directors. She was appointed a member of the Judicial Conference Committee on Federal-State Jurisdiction by U.S. Supreme Court Chief Justice John Roberts "John Roberts (Supreme Court)").