In 2004, to challenge District 68 incumbent Democratic Representative Tommy Head, Johnson ran in the August 5, 2004 Republican Primary, winning with 1,104 votes (77.9%),[3] and won the November 2, 2004 General election with 13,044 votes (55.3%) against Representative Head.[4]
In 2006 Johnson was unopposed for the August 3, 2006 Republican Primary, winning with 4,118 votes,[5] and won the November 7, 2006 General election with 10,158 votes (55.5%) against Democratic nominee Tim Barnes.[6]
In 2008 Johnson was unopposed for both the August 7, 2008 Republican Primary, winning with 1,471 votes,[7] and the November 4, 2008 General election, winning with 18,177 votes.[8]
In 2010 Johnson was unopposed for the August 5, 2010 Republican Primary, winning with 5,545 votes,[9] and won the November 2, 2010 General election with 10,804 votes (64.7%) against Democratic nominee Brett Ramsey.[10]
In 2012 Johnson was unopposed for both the August 2, 2012 Republican Primary, winning with 2,253 votes,[11] and the November 6, 2012 General election, winning with 18,376 votes.[12]