The former Inverness marksman notched for the first time in 13 months to halt the Buddies' barren run of five straight defeats.
The visitors took the lead four minutes before the break through Jim Hamilton but Falkirk equalised - despite Jackie McNamara being shown a straight red card - when Steve Lovell found the net in the 62nd minute.
The visitors made a promising start to the match and dominated possession during the early exchanges as the Bairns struggled to string successive passes together.
It was no surprise when St Mirren conjured up the first chance of the game after eight minutes. Stephen McGinn neatly lifted the ball over the Falkirk rearguard and Andy Dorman drilled a left-footed shot wide of Robert Olejnik's post.
Concerned by his side's poor start to proceedings, Bairns boss John Hughes was heard bawling at his players from the dugout.
The hosts finally managed to find their composure and, in a sweeping move in the 22nd minute, Kevin McBride connected with a header at the back post from Burton O'Brien's cross but was unable to get any power on his effort.
Falkirk survived another St Mirren attack in the 25th minute. Dorman did well to create room in the box for a shot and, although his effort beat Olejnik, defender Lee Bullen was on hand to clear the danger.
That scare appeared to act as a spur as the Bairns responded by creating two chances in quick succession.
Firstly, in the 27th minute, McBride headed well wide from Jackie McNamara's cross.
The midfielder then unleashed a powerful shot from 20 yards that clipped the top of the bar.
At the other end, McGinn was put clear by Hamilton but Olejnik did brilliantly to save his close-range shot and then block the youngster's effort on the rebound with his feet.
In an entertaining finish to the first half, McBride hit a shot inches wide of the post from long range and then blasted over in the 33rd minute after O'Brien's free-kick had St Mirren in a panic.
St Mirren dealt Falkirk a blow four minutes prior to the interval with the opening goal courtesy of Hamilton.
Former Bairns player Jack Ross' venomous shot across goal was palmed into Hamilton's feet by Olejnik and the striker placed the ball into the net.
Falkirk midfielder Patrick Cregg's frustrations got the better of him minutes into the second period when he lunged into a tackle with Hugh Murray and was subsequently booked.
Hughes' side had a purpose about their play following the break and Mark Howard did well to tip O'Brien's deft chip from 18 yards over the bar.
However, the home side were reduced to 10 men when McNamara went in hard on Hamilton on the far-side touchline and was shown a straight red card.
After receiving treatment, veteran striker Hamilton was able to continue.
Hughes responded by making two changes, introducing Scott Arfield ad Graham Barrett for Cregg and Arnau Riera.
Despite being at a numerical disadvantage, Falkirk levelled the score in the 62nd minute through Lovell.
Higdon challenged goalkeeper Howard from O'Brien's free-kick and the ball fell to Lovell, who found the net.
The far-side assistant referee had flagged for offside prior to Lovell scoring but referee Dougie McDonald gave the goal after conversing with his colleague.
Wyness restored St Mirren's narrow lead in the 73rd minute to end his goal drought.
Andy Dorman created the opening with a driving run down the left-flank before spraying a pass across the six-yard box for Wyness to place into the net with Olejnik stranded.
Hughes threw on his fourth striker when Mark Stewart replaced defender Dean Holden.
St Mirren somehow kept their lead intact in the 84th minute when a corner caused all sorts of problems.
Higdon hit the post before Lovell had an effort cleared off the line.