Studied electronic engineering at TAFE, communications engineer for a large corporation.
A record nine candidates nominated for the seat of Port Adelaide. The Liberal Party of Australia, Family First Party, and independent candidate Max James, who contested the previous election and gained a primary vote of 26.8 percent, 5.9 percent, and 11.0 percent respectively, did not contest the by-election.
On 21 September 2011, 642 voters were polled in the seat. Before either major party decided on a candidate, Labor's primary vote was at 37 percent (49.9 percent at the last election), the Liberals on 31 percent (26.8 percent), Johanson on 14 percent, the Greens on 11 percent (6.3 percent), and other independents with 6 percent.
On 18 January 2012, 475 voters were polled in the seat. Since the September 2011 poll, there had been a change of Premier, Labor preselected Close, Foley formally resigned from parliament, and the Liberal Party declined to field a candidate. Labor's primary vote was at 48 percent, Johanson on 23 percent, the LDP on 14 percent, Lawrie on 9 percent, the Greens on 3 percent, with remaining candidates on about 3 percent collectively.
On 1 February 2012, 402 voters were polled in the seat, with Labor on 44 percent, Lawrie on 18 percent, Johanson on 14 percent, the Greens on 12 percent, and remaining candidates including the LDP on about 12 percent collectively.
Under instant runoff voting with voters' full preference allocation, on the above polling and without a Liberal candidate, it was possible for one of several candidates to win. On how-to-vote cards located on all polling booths at each polling place, Briton recommended preferences to the Greens and then Labor, the Greens recommended preferences to Labor, Thomas had a split ticket recommending Labor or Johanson, while the remaining party and independent candidates including Johanson generally recommended preferences between each other in varying order. The by-election was expected to be a close contest on both eliminated candidate preference flows and the final TCP vote.
Labor retained the seat on a 52.9 percent TCP vote against Johanson, with a majority in seven of 11 polling places. Postal votes were included on 13 February, absentee and pre-poll votes were included on 14 February. Preference distributions occurred on 18 February. Results are final.
Neither a TPP or TCP swing could be produced, as the 2010 result was between Labor and Liberal rather than Labor and independent with no Liberal candidate. An increase or decrease in margins in these situations cannot be meaningfully interpreted as swings. As explained by the ABC's Antony Green, when a major party does not contest a by-election, preferences from independents or minor parties that would normally flow to both major parties does not take place, causing asymmetric preference flows. Examples of this are the 2008 Mayo and 2002 Cunningham federal by-elections, with seats returning to TPP form at the next election. This contradicts News Ltd claims of large swings and a potential Liberal Party win in Port Adelaide at the next election.
Johanson unsuccessfully contested the neighbouring seat of Lee at the 2014 state election with a primary vote of 11.2 percent.