He attended Wadham College, Oxford on a Rhodes Scholarship, and received his Doctor of Jurisprudence degree from the University of California, Berkeley School of Law in 1967.

Frohnmayer was elected as Oregon Attorney General in November 1980, defeating Democrat Harl H. Haas, Jr.,[4] and was sworn into office on January 5, 1981.

Popular Democratic incumbent–and former UC Berkeley School of Law classmate–Neil Goldschmidt withdrew after Frohnmayer's campaign manager, Donna Zajonc, said "...you've got to believe that the best family will win" at a news conference,[7] which was then reported by Jeff Mapes in The Oregonian.

[10] Frohnmayer subsequently lost the election to Barbara Roberts, the Democrat who was nominated after Goldschmidt's withdrawal, in a three-way race that included independent, Oregon Citizens Alliance-backed[11] candidate Al Mobley.

In April 2000, students protesting labor conditions at Nike blocked Frohnmayer from leaving his office, until they were arrested.

[14] Frohnmayer met Lynn Johnson, a native of Grants Pass, Oregon, and returned Peace Corps volunteer, while working in Washington, D.C., as executive assistant to Robert Finch, Secretary of Health, Education, and Welfare in the Nixon administration.

In 1983, during Frohnmayer's first term as Oregon's Attorney General, daughters Kirsten and Katie were diagnosed with Fanconi anemia, a rare and life-threatening recessive genetic illness.

[17] Frohnmayer was also a founding Director of the National Marrow Donor Program and served as a member of the Board of Trustees of the Fred Hutchinson Cancer Research Center.

Frohnmayer's upbringing was heavily influenced by his father Otto's dedication to the law and public service[18] and his mother MarAbel's love of music.

[19] His brother, John, served as chairman of the National Endowment for the Arts under the administration of President George H. W. Bush and briefly challenged incumbent senator Gordon Smith in the 2008 election as an independent.