The 25-year-old playmaker, who was outstanding at Hampden, revealed that he has already opened contract talks but that he had been contemplating a switch to England.
But McGowan believes that Saints' 3-2 silverware success over Hearts, which ended a 26-year major trophy drought and sealed the League Cup for the first time in the club's history, has swayed him toward nailing down his future with the Paisley club long term.
The former Celtic player also admitted that he feels he owes gaffer Danny Lennon a debt of loyalty after he resurrected a career that had stagnated at Parkhead and has now made him a Paisley cup-winning legend.
McGowan said: "We have been talking over a new deal and to be honest it has been a really tough call.
"Obviously you wonder, after having been with the club for a couple of seasons, if it is time to move on and try something fresh, maybe down south.
"But the club have been great with me and showed real loyalty to me during a time when other things off the field have made life tough.
"It is in my head now that maybe I need to repay that loyalty.
"I am really enjoying my football in a young St Mirren side that is evolving and only going to get better with the experience of winning a major trophy.
"For me all of that is starting to really make me think I should be staying here.
"The gaffer has been great with me and he took a chance on me and backed me when Celtic did not work out.
"Now I am a League Cup winner and that's just unbelievable, but we can push on from here.
"Next season why can't we be challenging for Europe?"
With Scotland gaffer Gordon Strachan a match analyst for the BBC – and selecting the Saints ace as his top performer – McGowan is hoping he has done enough to stray on to his radar.
He said: "Of course I have ambitions to play for Scotland and playing in cup semis and finals, and winning a trophy with St Mirren has got to help me in that regard.
"If the gaffer keeps this team together there could be a lot more big games to come.
"That would be a great platform to push on and try and get involved with Scotland."
However a Paisley cup triumph seemed all so unlikely as the Buddies suffered a bout of stage fright early on and, with only 10 minutes gone, disaster struck.
Skipper Jim Goodwin was unlucky to see a powerful slide tackle rob former Saints star John Sutton only for the ball to break to Michael Ngoo, who then fed Ryan Stevenson.
The Hearts ace twisted clear of Paul Dummett and smashed a 20-yard right-foot drive past the despairing Craig Samson as the men from the capital club rubber-stamped their early dominance.
A lack of any meaningful possession coupled with some edgy defending seemed to hint at the possibility that the Saints team – on average, considerably younger than their rivals – were in danger of a complete cup final freeze.
The sight of an animated Danny Lennon barking orders and imploring his men to greater effort underlined the fact that another concession would almost certainly be fatal.
But with the Paisley goal leading a charmed existence Saints hit back hard.
Stevie Thompson managed to nick a toe on to a David van Zanten pass and set Gary Teale free, who found Esmael Goncalves arriving 15 feet out to administer a composed finish.
The goal was the confidence boost Saints needed and the whole momentum of the game had pirouetted with it.
Within moments of the restart this amazing reversal of fortune was underlined when Dummet's previously wayward distribution was replaced by a sure-footed near post delivery that Thompson swept home with a left-foot flourish for his 15th strike of the season.
The game was swinging one way and then the other but in 65 minutes the decisive Buddie blow was landed.
Conor Newton dispossessed Mehdi Taouil 30 yards out and played a give and go with Goncalves before sprinting into the Hearts box and rasping a right-foot drive past Jamie MacDonald to put Saints 3-1 up.
But there was more drama coming and, after being denied by the crossbar, Stevenson latched on to a Ngoo pass and unleashed a left-foot drive across Samson to hand Hearts a late lifeline.
With a minute left Samson produced a great near-post stop to deny Stevenson's rocket in a cup classic.
After three minutes of added time, referee Craig Thomson's whistle ended a major trophy drought and made Lennon and his men immortals.