Prior to her tenure in the state legislature she served on the Port of St. Helens board and worked in the Oregon Department of Transportation.

[13] She replaced Betty Roberts as the chair of the Tom McCall lectureship committee at Oregon State University in 1992.

[15] Tony Federici, a member of the Port of St. Helens board from the fourth position resigned in January 1993, in order to take office in the state house from the 1st district.

[28] Following the September 11 attacks the House Special Task Force on State Emergency Preparedness was formed with Johnson being one of its members.

[30] Joan Dukes, a member of the Oregon Senate, was appointed to the Northwest Power and Conservation Council by Governor Ted Kulongoski in 2004.

[31] Johnson, Bill Blank, and Emil Nyberg were nominated by the Columbia County Democratic Committee as possible options to replace Dukes.

[38][39] Howard Dean, the former chair of the Democratic National Committee, called for Johnson to be replaced after she voted with the Republicans against voter registration legislation in 2013.

[4][46][47] An ethics investigation was launched against her on June 22, 2007, as she did not report profits of $119,000 from selling property connected to legislation she sponsored and she later paid a $600 fine.

She was sued by the driver in 2015, but Johnson's lawyers argued the lawsuit was frivolous, and a violation of the Oregon Constitution due to her being in transit to her complete her duties as an elected official.

[58][59] She announced on October 14, 2021, in an email that she was going to run as an independent in the 2022 gubernatorial election stating "[H]aving to choose between another left-wing liberal promising more of the same or a right-wing Trump apologist – is no choice at all".

[73] She stated to OPB in September that as governor she would lift the moratorium on capital punishment and enforce the death penalty.

[85] In 2002, Johnson voted in favor of the unsuccessful effort to overturn legislation to borrow $50 million for education against revenue made from a cigarette tax.

[91] Johnson opposed four pieces of gun control legislation in 2013, stating "I would do something meaningful rather than symbolic" and wanted more mental health access instead.

[93][94] She is a member of the National Rifle Association and received an "A" rating and endorsement from the NRA Political Victory Fund during the 2014 and 2018 elections.

[95][96] She voted against legislation in 2019 to redefine aggravated murder and limit its scope, the only crime in Oregon which is eligible for the death penalty.

She blames recent drug legalization, such as through 2020 Oregon Ballot Measure 110, for driving the crisis and would attempt to repeal it, while also focusing on deregulating housing development.

[101] She stated that "Planned Parenthood now is a wholly owned subsidiary of the Democrat Party" after failing to gain its endorsement during the 2022 gubernatorial election.

[105] She received a lifetime score of 64% from the League of Conservation Voters,[106] and has a record of voting against legislation to combat climate change,[107] such as Oregon House Bill 2020.