Longwell agreed to take caretaker charge of the Coasters following the departure of Kevin Phillips a week ago.
It was understood that the National League club would begin their search for the former England striker’s replacement this week.
But chairman David Haythornthwaite was so impressed with what he watched in the win at Altrincham that Longwell will stay in place until May.
The 50-year-old says keeping the Fylde from a National League North return is the only goal.
Longwell told the club’s website: “The club have asked us to continue supporting the players and asked us to keep it going which we’re obviously more than happy to do
““I was brought in to provide support and I’m going to continue to do exactly that for the players. I told the players that I will just continue to work hard, just like all the staff in there and we will do our utmost to get the best out of the players and make sure they keep working hard.
“What we proved on Saturday is that if you do that and everyone works hard, together, then results come and we need to do more of that over the next 14 games.”
Goalkeeper coach Chris Neal will assist Longwell for the remaining two months of the season. Premier League legend Phillips was appointed in October, but failed to turn around the club’s National League fortunes.
Fylde remain in the bottom four and this weekend DAZN viewers will see if the caretaker will get another win when the cameras bring their trip to Gateshead to life.
The strugglers then host Hartlepool United next Tuesday at Mill Farm.