Senator Johnson became the fifth incumbent to lose reelection joining Democrat James Shields in 1859, Democrat Charles Towne in 1901, Republican Moses Clapp in 1916 (primary), and Republican Frank Kellogg in 1922. This remained the most narrowly decided U.S. Senate election in Minnesota history until Al Franken's 0.01-point win over Norm Coleman in 2008.
Schall was an attorney from Excelsior, Progressive-turned-Republican U.S. Representative (CD 10, 1915-1925), and candidate for U.S. Senator in 1923.
Farrell was a dairy farmer from Carver, former state dairy and food commissioner, Republican nominee for SD 25 in 1910, non-partisan nominee for SD 21 in 1914, and Democratic nominee for the 3rd CD in 1918.
Birmingham was a resident of Minneapolis whose campaign platform was to repeal all laws checking the manufacture, sale, and possission of light wines and beers. He was nominated by petition.
Keefe was a resident of St. Paul and Republican candidate for Governor in 1920. He was nominated by petition.