The two-time California governor is 74 years young. He can still shoot hoops, drop and do push-ups, hike Yosemite and says he recently ran 3 miles in 29 minutes.
Brown's age, and the fact that he's had a long political career, gave Christie plenty of material for his speech to the California delegation.
"California made a bad choice by going with an old retread, who -- let me tell you this -- I cannot believe you people elected Jerry Brown over Meg Whitman," Christie said.
Christie is known for speaking his mind and throwing verbal punches. He referred to Brown as an "old retread" for still being in office.
"He won the New Jersey presidential primary over Jimmy Carter when I was 14 years old," he added.
Christie's comment got plenty of laughs. Brown didn't fire back immediately, but when he later met with union workers in Los Angeles, Brown defended the experience that he says comes with his age.
"I may know a hell of a lot more than you," Brown said. "Because when you were 14, I was passing the Farm Labor Bill. I was passing worker protections in California."
But he didn't stop there. Brown took a jab at the larger girthed New Jersey governor.
"And I hereby challenge Gov. Christie to a 3 mile race, a push-up contest and a chin-up contest and whatever he wants to bet. I have no doubt of the outcome," he said.
A spokesperson for Christie responded to Brown's challenge by saying: "Defensive much? This is what it looks like when you're out of ideas I guess. Except, of course, raising taxes."