The visitors would have been forgiven if they had come and played for the draw, but in the early stages they took the game to the home side and after four minutes Thomas Scobbie's cross was headed goalwards by Carl Finnigan but Derek Soutar held easily.
Five minutes later a Jack Ross cross was this time met by the boot of Finnigan, but was once again well saved by Soutar.
Less than 30 seconds later another Ross cross was headed inches wide by Finnigan.
The Bairns were then made to pay for their missed chances when a Scott Severin long throw from the left was flicked on by Alexander Diamond at the near post and Chris Maguire nipped in to head past Robert Olejnik.
Ten minutes before the break Soutar sent a free-kick from deep in his own half towards the head of Lee Miller, whose flick found Maguire, who in turn touched the ball into the path of Richard Foster, but keeper Olejnik came quickly off his line to block what could have been a killer second goal.
Falkirk began the second half looking for the goal that would put them back in the driver's seat and just a minute into the second period a wonderful pass by Scott Arfield gave Graham Barrett a clear sight of goal, but Foster redeemed himself with a slide tackle as Barrett prepared picked his spot.
Three minutes later a goal did arrive for the visitors, this time an Arfield cross was touched goalwards by Finnigan and his touch was spilled by Dons' keeper Soutar. Finnigan himself reacted first to bundle the ball home from two yards.
In the 55th minute the home side were denied what looked like a stonewall penalty when Foster's cross appeared to hit the raised arm of Darren Barr at the far post, but referee Michael McCurry waived away the claims from the Dons players.
On 69 minutes Aberdeen almost got their noses back in front with a rasping effort from Alan Maybury which flew just wide of the upright.
Less than a minute later, however, Falkirk's Finnigan should have had the visitors ahead after being put clear just six yards out by Barrett, but the big striker scuffed his effort and Soutar gathered gratefully.
With seven minutes left on the clock Miller sent Sone Aluko down the left and inside the area.
He cut the ball back from right on the by-line to Maguire, who turned superbly and poked the ball home from a tight angle in off the foot of the far post, to send the home fans into raptures and guarantee the Dons a top-six finish.