The 40-year-old told ESPN: "He put his money right where his mouth is, and I put my money right where my mouth is. It's good for both parties.
"[Point guard] Mike Conley and I were talking about we've been together for a long time, brother. Now we've got another three-, four-, five-year run on this deal.
"I am 100% committed to leading the Grizzlies and I could not be more proud to call Memphis home. I'm here to tell you this thing is going to be very positive."
Joerger, who was appointed last summer, led the Grizzlies to the playoffs during his first season in charge of the side.