The Norwegian had trailed compatriot Andreas Stjernen following the first jump but his second attempt of 246 metres earned the 27-year-old 223.9 points, enough to seal the title.
Stjernen opened up with a jump of 239 metres, earning 222.8 points and a lead of the competition.
Johansson snatches Raw Air title in Vikersund
18/03/2018 AT 17:49
Johansson was in second place and trailed his countryman by 2.4 points following a jump of 232 metres.
But his second jump of 246 metres was the best in the field in Norway and enough to get 444.3 points overall, beating Stjernen by 5.4 points.
Winner Robert Johansson of Norway is gratulated by his teammate Andreas Stjernen.
Image credit: Reuters
Daniel Andre Tande finished in third place with a total of 436.6 points, ensuring it was an all-Norwegian podium – Slovenia's Domen Prevc was fourth.
Overall World Cup leader Kamil Stoch was 11 points off the podium places as his tally of 425.6 was only enough to finish sixth.
However, Stoch is comfortably clear at the top of the World Cup standings with two meets to go, both in Planica, Slovenia, taking place on March 23 and 25 respectively.
Stoch is on 1243 points with Richard Freitag, who placed eighth in Vikersund, in second place on 990 and Andre Tande is sitting in third, 65 points off the German.
Raw Air: Kamil Stoch reaches 237m on second jump in Vikersund
18/03/2018 AT 17:46
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