From 1990 to the 2000s, Prahl was one of Sweden's most successful managers, winning three league titles. He debuted in 1992 in
Allsvenskan with
Trelleborgs FF. He won the league since then with both
Malmö FF and
Halmstads BK. On 1 January 2006, he took over
Viking from
Roy Hodgson. However, his spell with the
Stavanger-based club proved unsuccessful, and he was fired in September 2006 on the back of seven losses in eight league matches, with the team on the bottom of the
Norwegian Premier League table. Prahl returned to Trelleborg and managed the club until his retirement in 2011. ==Honours as manager==