Altrincham beat Guiseley in the Conference North play-off final at Moss Road thanks to Greg Wilkinson's winner in the last minute of extra time.
The Cheshire side will be back in the top flight of non-league football for the first time since 2011.
Alty took the lead on 50 minutes as James Lawrie shot in off the post but Guiseley replied with 19 minutes left when Jake Lawlor headed in a corner.
Substitute Wilkinson netted in the 120th minute to seal victory.
Altrincham were beaten play-off semi-finalists last season and, with over 4,600 fans in attendance, the final whistle sparked a pitch invasion.