It was Vardy who first came close to opening the scoring with just two minutes on the clock, as he skipped past one defender before sending his effort wide of the mark.
Both sides traded blows in the first period – Jannik Vestergaard and Lars Stindl for the visitors, while Marc Albrighton, Wes Morgan and Wilfred Ndidi had opportunities at the other end.
The Foxes then fell behind just 20 seconds after the break. The ball dropped to Thorgan Hazard on the edge of the box before the Mönchengladbach No.10 sent an effort into the top corner.
But that only seemed to spur on Craig Shakespeare’s men, who drew level 20 minutes later. Matty James sent a pin-point pass over the top of the defence into the path of Vardy, who brought the ball down with a fine first touch before finishing past Yann Sommer.
Sommer, who earlier denied Shinji Okazaki and Vardy with two good stops, was beaten again by City’s No.9 with just over 15 minutes to play.
Kelechi Iheanacho came off the bench to make his first appearance for the Club and made an immediate impact by setting up Vardy for his second. The Nigeria international looked like he would go for goal, but unselfishly played in his strike partner.
Iheanacho departed the pitch shortly after, though. Fouled by Laszlo Benes on the halfway line, he appeared to pick up a knock and was withdrawn as a precaution by Shakespeare with around five minutes to play.
Comfortable in the closing stages, only Hazard’s low drive threatened the City goal – a combination of Morgan and Daniel Amartey protected Leicester’s lead as they rounded off their pre-season with a win.
Key moment
Aiming to preserve his side’s one-goal advantage, Borussia Mönchengladbach stopper Yann Sommer pulled off two superb saves to deny Jamie Vardy and then Shinji Okazaki around the hour mark.
But the Foxes persevered and it was Vardy who grabbed the crucial equaliser to give his side a foundation to go on and win the game.
Who impressed?
England international Jamie Vardy looked as sharp as ever and could have had a hat-trick were it not for the impressive reactions of Yann Sommer.
Vardy’s opener – his first of pre-season – was taken brilliantly before some smart positioning saw him grab a second just seven minutes later.
Coming up…
Following seven pre-season fixtures, the Foxes can now start looking forward to their 2017/18 Premier League opener against Arsenal.
City head to Emirates Stadium on Friday evening to face the Gunners before a fixture at King Power Stadium against Brighton and Hove Albion follows on Saturday 19 August.