Two strikes in the first half, the second a silky team passing move rounded off with a side-foot from the Bairns' top marksman, was complemented by a second half penalty at Balmoor.
The Bairns were in complete control of the second period but the home side had threatened early on and who put up a fight, and pulled one back through an own goal off Mark Durnan to leave the Bairns deservedly ahead at the break, but not by much.
The ordering off of David Ferguson for the foul on Conor Sammon that conceded the penalty ended the Blue Toon's hopes and only some good goalkeeping from Greg Fleming and poor fortune for McManus unable to add to his tally kept the score low.
Sammon had been restored to the starting line-up ahead of David McMillan after a positive showing from the bench against Dumbarton. The Bairns also included Graham Bowman, a former Bairn, as the trialist goalkeeper with Callum Erskine's three permitted squad inclusions used up by managers Lee Miller and David McCracken.
Sammon was the perfect foil for McManus in a good Falkirk showing, backed well by midfielders Charlie Telfer and Aidan Connolly.
However it was a burst from Morgaro Gomis that created the opener as the little midfielder left ex-Bairn Cameron Eadie in his wake and zipped by Mick Dunlop into the six-yard area and the loose ball after a shot was tucked away by McManus.
The bairns continued to push for another though Peterhead tiwce threatened down their left wing - attacking Michael Doyle and Mark Durnan through Derek Lyle. Only good recovery wpork from the centre half denied Lyle a breakaway and test of Robbie Mutch on a quiet afternoon for the goalkeeper.
Durnanan's afternoon took an unfortunate turn but only after McManus had put the Bairns comfortably in front with a lovely move.
Michael Doyle charged down the right and rather than cross early from deep for the advancing McManus and Connolly progressed into the box. A clever cut-back was stepped over by Charlie Telfer into the path of McManus and he stroked the ball beyond Fleming from 18 yards.
The two-goal cushion lasted just two minutes when Peterhead advanced down the left again and after a set-piece from the wing the ball beat Robbie Mutch with Durnanan the last to touch it.
The Bairns started the second half brightly as darkness fell, and when Sammon and Connolly charged through Ferguson only had one option and took his punishment for a foul on the nippy little midfielder. McManus only knew one option too and sealed his hat-trick by slamming the ball down the middle and ensuring a comfortable win.
He could have had another with a low cross that flashed inches in front of him at the backpost just after the 65th minute but Falkirk, and another cut back from Doyle that bobbled just in front of him but against ten men the misses were never going to be costly and the Bairns didn't look like letting go of the game after that.
David McMillan, Rafa de Vita and Robbie Leitch were introduced for Telfer, McManus and Gomis to take a bow after a positive afternoon for Falkirk ahead of a Scottish Cup trip to Arbroath next week.