Now, he faces a re-build ahead of the start of the women's Scottish Premiership as he loses two players.
Hadfield's squad have not lost a game since September and they went into the nerve-jangling promotion/relegation play-off contest against their Dundee-based rivals on a high.
Goals by Alex Dugan, Heather Croll, Kayleigh Justice and Liss Deans sealed promotion for Edinburgh-based Grange, who finished runners-up to Capital rivals Inverleith in the National League.
The capitulation by the Dundee side, who finished second bottom of the Premiership with only three wins in 21 league games, completes a spectacular fall after they won the Premiership on ten occasions between 2001 and 2013.
Grange coach, Sean Hadfield, a former Scottish international goalkeeper, said: "The girls targeted promotion at the start of the season and they have now lost a game since September. Ending in the play-offs was magic and we set a target which we have achieved.
"Only five or six girls have played previously for the first team and we recruited two experienced senior players so this is nearly a new team and everything has come together brilliantly this season."
He added: "To achieve 20 games unbeaten and ending up in the play-offs in absolutely magic. I told them before the game to go out and enjoy it. We respected Grove, but we knew if we played our game we would win.
"We also knew that if we scored the ascendancy would be with us and that is what happened. We have the resilience to see out results."
Hadfield added: "It was a real team effort. We lose a couple of players next season so it is re-build again but we will go up and see if we can stay up in the Premiership."
Meanwhile, FMGM Monarchs edged out Tayside rivals Dundee Wanderers 3-2 at Peffermill in the men’s promotion/relegation play-off with goals from Mark Stevenson, Callum Boag and the game-winner from Ross Glashan.
Monarchs, who finished second behind Edinburgh club Erskine Stewart's Melville in the National League title race, raced to a 2-0 lead before their rivals clawed their way back to level at 2-2 on the third quarter hooter thanks to a Bobby Ralph double to set up a nerve-jangling final session.
But Monarchs held their nerve against their rivals who finished second-bottom of the Premiership to slot the all-important counter to take them up.