Humphrey was a resident of Minneapolis, former political science professor at Macalester College (1943-1944), radio news commentator, Mayor of Minnneapolis (1945-1948), U.S. Sneator (1949-1964), and Vice President (1965-1969).
MacGregor was an attorney from Plymouth and sitting U.S. Representative (CD 03, 1961-1971).
Strebe was a resident of Minneapolis and taxicab driver. Strebe was nominated by petition.
Braatz was a resident of Plymouth, ran a self-employed home repair business, and Industrial Government nominee for Governor in 1962, for U.S. Senate in 1964 and 1966, and for the 5th CD in 1968. Braatz was nominated by petition.