Three goals before half time put Rovers well on their way to the most famous result in their history, as they successfully saw things through to reach the fourth tier of English football.
It is more heartbreak for Tranmere, meanwhile, who finished nine points above their opponents in the table but failed to turn up on the day and will play non-league football next term for a third successive year.
The match started in a frantic fashion with both teams looking to attack, but it was Forest Green who opened the scoring 11 minutes in through on-loan Wigan Athletic forward Kaiyne Woolery, who was allowed to carry the ball forward before picking his spot.
Tranmere were being nullified in attack following that early blow, with the next chance falling to Mark Ellis who could not quite direct his header on target.
The next goal went the way of the Micky Mellon's side, though, as Connor Jennings matched Woolery by scoring a pearler from outside the box to temporarily level things up - his seventh goal in eight matches.
Forest Green, beaten by Grimsby Town at this stage 12 months ago, were lucky not to fall behind soon after when James Norwood raced through but was denied from a one-on-one position.
The match soon swung firmly in Forest's favour, though, with Christian Doidge cutting inside on his right and finding the back of the net, three minutes before Woolery bagged his second following some slack play at the back.
Tranmere were dominating things for large parts of the second period, but Forest Green ace Woolery should have done better with his chance 70 minutes in after getting in behind.
Despite their efforts Tranmere just could not find a way through, however, meaning joy for Forest Green in front of the 18,801 fans in attendance at Wembley Stadium, as they look forward to their first foray into the EFL.