A wonderful end-to-end match saw USMNT youngster Mix Diskerud score for Rosenborg, but ultimately Molde claimed a 4-2 win and the Norwegian Cup with it.
The victory gives Molde a berth in the qualifying round of next year’s Europa League.
It also hands manager Ole Gunnar Solskjær a trophy in each of his first three seasons with Molde, having won the league title the previous two years.
Diskerud scored in the 17th minute to level the scoreline at 1-1, rifling a shot home from 22 yards out.
It came less than a minute after Molde had opened the scoring through Knut Olav Rindarøy.
Rosenborg’s Tore Reginiussen headed in a corner early into the second half for a 2-1 lead, but it all fell apart from there as Molde picked up three goals in the final 20 minutes.
The loss means Rosenborg take second place in both the league table and the cup, finishing just a single point behind Strømsgodset for the Tippeligaen. The second-place finish will earn Diskerud’s club a spot in next year’s Europa League.