Goals from trialist Jordan Allan and new signing Dennon Lewis gave the Bairns the win, with Andy Graham scoring for the hosts.
It was a quiet opening to the game, with a few half chances for Paul Hartley's visitors. The first real chance came on 33 minutes when Tom Dallison's powerful header was cleared off the line.
Tommy Robson dragged wide just two minutes later as the Bairns turned up the pressure.
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The best chance of the first period came with the last action before the whistle. Tom Owen-Evans played a lovely through ball into Dennon Lewis and the striker was denied by Neil Parry in the Alloa nets.
Into the second half and Falkirk scored almost immediately. Tommy Robson's cross was nodded into the path of Dennon Lewis who made no mistake second time of asking and hammered in off the crossbar.
The game was less fragmented by changes than the win against Airdrieonians on Saturday, but Falkirk were pegged back when Andy Graham equalised on 73 minutes.
Jim Goodwin's side, though, weren't level for long. Trialist Jordan Allan volleyed home from Dylan Mackin's knockdown. Mackin came on as a 60th minute sub, having officially signed less than two hours before kick-off.
Falkirk held on for a moral boosting victory against their Championship rivals, despite a few late Alloa chances.
The Bairns' first competitive fixture is this Saturday at home to Montrose in the Betfred Cup.