Justice McDonald was born November 22, 1936 in Butte, Montana. He is married and has four grown daughters.
He graduated from Stanford University in 1958 with a B.S. degree in Industrial Engineering. He received his LLB degree in 1961 from the University of California School of Law (Boalt Hall) at which he was revising editor of the California Law Review and a member of the Order of the Coif. He received his LLM degree in 2001 from the University of Virginia School of Law.
Following law school he studied Indian Constitutional Law at the University of Bombay in Bombay, India and was a law clerk for California Supreme Court Justice Raymond E. Peters.
He was in the private practice of law from 1963 until appointed to the Court of Appeal by Governor Pete Wilson in June 1995.