Carlson was a development consultant and attorney from St. Paul, Republican nominee for HD 55B in 1996, Independence nominee for the 4th CD in 2010 and 2012, DFL candidate for the 4th CD in 2016, and DFL candidate for U.S. Senate in 2018.
Terrell was a business consultant from Minneapolis and the party-endorsed candidate.
Shephard was a former St. Paul dentist, convicted felon, and fugitive living in Rome, Italy. Shepard was a Republican candidate for U.S. Senate in 2002 and 2008, candidate for the 4th CD in 2004, 2006, and 2010, and DFL candidate for U.S. Senate in 2012.
Williams was a small business owner and farmer from Brownsdale, Independence candidate for U.S. Sneate in 2006, 2008, and 2014, Independence candidate for Lieutenant Governor in 2010, and Independence nominee for U.S. Senate in 2012.