He studied at the Stockholm School of Economics, and was the leader of the Centre Party youth organisation from 1969 to 1971.

In 1987 he succeeded Karin Söder, who stepped down for health reasons, as the leader of the Centre Party.

When the centre-right regained power in 1991, Johansson became Minister for the Environment in the Carl Bildt government, but left the post over his opposition to the construction of the Oresund Bridge in the summer of 1994, shortly before the Social Democrats regained power in the September elections.

[1] After his withdrawal from politics he has been appointed as Chairman of the board of various institutions and companies.

Most notably, he was the chairman of the Swedish state-owned alcohol monopoly company, Systembolaget, between 2002 and 2009.