Career
Davidsen started his career with NSÍ Runavík in the Faroe Islands, in 2004 he signed a trainee contract with Premier League club Everton and was part of U19 squad. In 2006, Jóhan Troest Davidsen went to NSÍ Runavík where he played half a season. The other half of the season Davidsen played for Skála ÍF, after which he returned to NSÍ.
In 2007, Davidsen became national champions with NSÍ Runavík.