In 1985, Matheson joined the faculty of the S.J. Quinney College of Law at the University of Utah. There, Matheson primarily taught constitutional law, criminal law, and civil procedure.[4] Matheson was also extensively involved in law administration and law reform efforts, serving as a vice-chair of the Utah Constitutional Revision Committee, a chair of the Utah Supreme Court Advisory Committee on the Rules of Evidence, and a member of the Utah State Bar Commission. Matheson was also involved in efforts to expand legal aid in Utah, establishing a pro bono Initiative at the S.J. Quinney College of Law and serving on the Board of Trustees of the Legal Aid Society of Salt Lake.[4]
During his time as a law professor, Matheson contributed to various other institutions during leaves of absence. From 1988 to 1989, Matheson served as the Deputy County Attorney for Salt Lake County.[5] From 1989 to 1990, Matheson was a visiting professor in the Frank Stanton Chair on the First Amendment at Harvard University's John F. Kennedy School of Government.[4] From 1993 to 1997, Matheson was the United States attorney for the District of Utah.[5]
Matheson served as dean of the S.J. Quinney School of Law from 1998 to 2006.[5] After concluding his deanship, Matheson spent his one-year sabbatical as a Public Policy Scholar at the Woodrow Wilson International Center for Scholars in Washington, DC.[5]
From 2007 to 2008, Matheson chaired the Utah Mine Safety Commission, which was formed in response to the Crandall Canyon Mine disaster and charged with improving mine safety and disaster response in the state.[4]
Hatch, an establishment conservative Republican from Utah, supported Matheson and helped shepherd the nomination through the Senate.[9] On December 22, 2010, the U.S. Senate confirmed the nomination. Matheson received his judicial commission on December 27, 2010.[6]