Representative Murr attended Texas A&M University, receiving a bachelor's degree, summa cum laude, in Agricultural Development with an emphasis on economics and policy. Following graduation, he worked toward his master's degree at A&M and earned his teaching certification, completing his student teaching in Mason. He subsequently graduated with the highest honors from Texas Tech University School of Law. In 2008, Representative Murr was elected Kimble County Attorney and then later appointed to the position of County Judge.

As County Judge, Representative Murr presided over hundreds of criminal, civil, and probate cases and was never overturned on appeal. In his term of office, he slashed county spending by 31% by cutting waste and inefficiency. Under his leadership, Kimble County today retained one of the lowest tax rates in the state, maintaining zero debt and incurring no future pension obligations. Representative Murr continued to serve as Kimble County Judge until late 2013, when he announced his candidacy for state office.

Representative Murr currently serves as the Chairman of the House Committee on General Investigating. During his tenure in the House, he has served on the Corrections Committee (Chair), Redistricting Committee, Transportation Committee, Culture, Recreation and Tourism Committee, Rules and Resolutions Committee, Ways and Means Committee, Judiciary and Civil Jurisprudence Committee, State Federal Power and Responsibility Committee (Vice Chair), Local and Consent Calendars Committee, Juvenile Justice and Family Issues Committee (Vice Chair), Criminal Jurisprudence Committee, Select Committee on Mental Health, the Select Committee on Opioids and Substance Abuse, and the House Interim Study Committee on Aggregate Production Operations.

Representative Murr lives on the family ranch in Junction with his children, Coke, Jackson, Caroline, Finn, and wife, Amanda. Murr raises cattle, maintains a general law practice and is a member of Trinity Episcopal Church in Junction.