Gallagher was an attorney from Minneapolis and the son of retiring Associate Justice Thomas F. Gallagher. The incumbent had filed for reelection but withdrew on July 15, 1966 stating he would retire at the end of his term.
Peterson was an attorney from Minneapolis, former state Representative (HD 36, 1959-1963), and Republican nominee for Lieutenant Governor in 1962.
Knutson was a resident of Minneapolis and Fourth Judicial District Judge.
Foley was a resident of Wabasha, Third Judicial District Judge, former Wabasha City Attorney (1949-1959), former national commander of the American Legion, and candidate for Associate Justice of the Supreme Court in 1978.
Popvich was an attorney from Stillwater, former state Representative (HD 40, 1953-1963), eventual Associate Justice of the Supreme Court (1987-1989), and Chief Justice of the Supreme Court (1989-1990).
Schultz was a resident of St. Paul, Second Judicial District Judge, and former state Senator (SD 37, 1951-1963).