Perez set the ball rolling after just seven minutes and although Jordan Hugill swiftly restored parity, Christian Atsu calmed nerves with a second goal on the stroke of half-time.
Matt Ritchie's 65th-minute penalty after Paul Gallagher had been dismissed for deliberate handball and a second from Perez ensured the Magpies could not be caught either on the night or in the table, to the delight and relief of a crowd of 50,212 at St James' Park.
Newcastle's return to the top flight was confirmed 348 days after arch-rivals Sunderland's 3-0 win over Everton condemned them to the drop as Benitez's decision to stay on was rewarded in style.
They got off to the perfect start when, having already seen Aleksandar Mitrovic come close to his fifth goal of the season against the Lilywhites with a curling effort from the edge of the box, they took a seventh-minute lead.
Jamaal Lascelles flicked on Ritchie's inswinging corner and Ciaran Clark prodded it to Perez to stab home at the far post.
However, their joy lasted just seven minutes when returning keeper Rob Elliot, who had already blocked Daniel Johnson's shot with his legs after Gallagher has split the Magpies' defence with alarming ease, was unable to repeat the feat when Hugill met Tom Barkhuizen's cross in front of goal.
The visitors were targeting right-back Vurnon Anita on the break, repeatedly playing the ball in behind him to good effect, although Benitez's men gradually eased their way back into the game and restored their lead on the stroke of half-time.
Isaac Hayden capitalised on a mix-up between Johnson and Alan Browne on halfway before racing forward to find Mitrovic, who laid off his pass for Atsu to fire home.
Preston keeper Chris Maxwell blocked a Perez shot within seconds of the restart as the Magpies went for the kill, but Barkhuizen only just failed to pick out Hugill at the far post after getting in behind Anita once again.
But the game changed with 25 minutes remaining when North End skipper Gallagher was dismissed for handling Hayden's shot on the line handball and Ritchie thumped home the resulting penalty, and Perez increased the advantage to 4-1 just two minutes later when Jonjo Shelvey's corner came back off the post and went in off him.
Source : PA