The 51-year-old had failed to preside over a win in his first 12 matches but first-half goals from Keith Treacy, Billy Jones and Iain Hume made it a lucky 13 for Brown a year ago to the day since he was sacked as Hull boss.
Treacy finished off a superb pass from the impressive Hume for the opener and Jones bundled home a second from a corner before Hume’s diving header put Preston 3-0 up and in total control.
The famous old Lancashire outfit still have a massive fight on their hands to beat the drop – they now lie 10 points adrift of safety – but with a home game against Coventry next up on Saturday, Brown may feel his luck is beginning to turn at just the right time.
Scunthorpe’s first-half display was as bad as anything witnessed in the Championship all season and on this evidence they will playing their football in League One next term.
Ian Baraclough’s men failed to create a single opening in the opening 45 minutes, much to the disgust of the home supporters who booed their team off at half-time and again at the final whistle.
In the 19th minute, Treacy crossed dangerously from the left flank and Eddie Johnson headed over the crossbar and then Chris Brown shot over from inside the 18-yard box.
Brown was wasteful again in the 31st minute when he nodded over from Ricardo Gardner’s superb delivery but the breakthrough arrived a minute later.
Hume broke from deep and slipped a superb pass into Treacy, who beat the offside trap and drilled a low right-foot shot into the bottom left-hand corner.
Five minutes later Preston had their second when Treacy’s inswinging corner from the right found Jones who gleefully bundled home from point-blank range.
Johnson then blazed wide from eight yards out in the 40th minute from Hume’s intelligent pass but Preston claimed their third two minutes before the break.
A deep cross into the box was headed down by Brown into Hume’s path and the Canadian stooped to nod into the net from six yards.
Baraclough made a substitution shortly before the hour mark and another just after but it was Preston who looked more likely to add any further goals.
Johnson was wasteful again when he tried to dribble his way through the home defence and when Scunthorpe striker Joe Garner hit a 20-yard shot into Iain Turner’s arms with 15 minutes remaining, it was the hosts’ only effort of note during the entire 90 minutes.