Forte, 24, opened the scoring in the 33rd minute on Saturday and struck again in similarly clinical fashion 11 minutes later.
His first league goals of the season effectively settled the match by half-time and Michael O'Connor's second-half penalty added gloss to a first home win of the season for Nigel Adkins' men.
Despite the presence of former Holland international Edgar Davids, who was played at left-back again, Palace were second best throughout although both sides went close to scoring during a lively opening.
In the second minute, Palace midfielder Kieran Djilali drilled a left-footed shot wide from 12 yards out and four minutes later the hosts went close.
Iron midfielder Michael Collins collected possession 20 yards from goal and drilled a fierce shot which Eagles centre-back Claude Davis did well to block.
Collins - a close-season signing from Huddersfield - went even closer in the 10th minute when when he hit a fine right-footed shot from 12 yards which drew a fine parried save from Julian Speroni.
Scunthorpe continued to probe but the visitors went close in the 13th minute when a curled 20-yard shot by Kieron Cadogan was blocked by Iron defender Rob Jones.
The hosts began to build up a head of steam and in the 31st minute Chris Dagnall drilled in a right-footed shot from 12 yards which drew a smart stop from Speroni.
Two minutes later, Scunthorpe led when Forte connected with a left-wing cross by Cliff Byrne and drilled a left-footed shot into the net from 12 yards.
Forte's second arrived on the stroke of half-time when he volleyed right-footed into the bottom left-hand corner from 18 yards.
That effectively settled the match but Palace almost earned a lifeline five minutes after the break when Jonathan Obika volleyed wide from 12 yards out.
Yet Forte almost claimed his hat-trick goal moments later with a fine shot that drew an equally impressive save from Speroni.
Shortly before the hour mark, Palace went close again when Cadogan's cross was headed over the crossbar by Obika.
Sam Togwell curled a delightful effort just wide but in the 71st minute Scunthorpe claimed their third goal.
Alex Marrow fouled Forte and O'Connor stepped up to fire a right-footed shot into the top left-hand corner.