A member of the Minnesota Democratic–Farmer–Labor Party (DFL), she represented District 37 in the northern Twin Cities metropolitan area.

Johnson attended Metropolitan State University, Minneapolis Community College—graduating with an A.A., Concordia University—graduating with a B.A., and Harvard University—graduating with a M.A.

[1] Johnson was first elected to the Minnesota House of Representatives in 1986 and was re-elected every two years until she retired in 2000.

[1] Johnson ran unsuccessfully for election to the United States House of Representatives in 1992.

Johnson was married to Richard H. Jefferson, who served in the Minnesota House of Representatives from 1987 to 1999.