Johansen started Nordic combined at the age of four. He contested his first FIS competitions in 2004. At the Junior World Championships in Zakopane in 2008 , he won the bronze medal with the team. He finished eighth in the sprint and seventh in Gundersen. A year later at the Junior World Championships 2009 in Štrbské Pleso he won gold with the team and reached 10th place in Gundersen and 11th place in sprint. On December 5, 2009, he made his debut in the Nordic Combined World Cup in Lillehammer . Already in the first two competitions he reached the points. At the Junior World Championships 2010 in Hinterzarten he won silver with the team and came ninth in the individual on the large hill. After the Junior World Championships, he also started in the Continental Cup. He finished the 2009/10 World Cup season in 50th place in the overall World Cup ranking.