The England striker netted twice in seven second-half minutes to overturn a one-goal deficit and secure his side's second win of a lean pre-season.
Vardy's star turn was somewhat overshadowed when Kelechi Iheanacho, who had helped to set up Leicester's winner, limped off shortly after coming on for his debut, but Foxes boss Craig Shakespeare later insisted the star signing's withdrawal was only precautionary.
"I am still looking to find out, I don't know whether it is ankle or Achilles - but he seems fine," said Shakespeare.
"The first thing is the physios and they aren't showing great concern, which is a good sign."
Thorgan Hazard had earlier put the visitors ahead with a brilliant curling effort just after half-time, with Bundesliga outfit suffering an injury worry of their own when midfielder Tobias Strobl was forced off on a stretcher.
Leicester open up the new Premier League season when they travel to take on Arsenal on Friday at the Emirates Stadium.