Kushner is far less well known than his wife, Ivanka Trump, but is clearly a force to be reckoned with, wielding tremendous influence behind the scenes.
It's widely assumed in political circles that the sacking of Christie was at least partly an act of personal payback by Kushner. Back in 2004, then-U.S. Attorney Christie convicted Kushner's father, Charles Kushner, on a variety of charges including tax evasion, witness tampering and making illegal campaign contributions.
The elder Kushner got the maximum sentence of two years in prison, in part because Christie wrote a tough memo calling Kushner's actions "fiendish." Jared Kushner regularly visited his father during the year he served behind bars -- and years later, reportedly helped kill Christie's chances of becoming Trump's vice-presidential running mate.
With no love lost between the men, it looks like Kushner came out on top again, showing a flair for the hard-knuckled political infighting that is a staple of life in the jungle warfare of Washington.
It's not clear what formal role Kushner will play after Inauguration Day. During Trump's first post-election visit to the White House, cameras caught Kushner walking and talking with President Obama's chief of staff, Denis McDonough, setting off rumors that Kushner might occupy the same position in the Trump White House.
That didn't happen: Trump tapped Reince Priebus for the chief of state position. Despite his family connection -- in fact, because of it -- there's a good chance federal law will prohibit Kushner from holding any government position. According to Title 5 Section 3110 of the US Code, "a public official may not appoint, employ, promote, advance, or advocate for appointment, employment, promotion, or advancement ... any individual who is a relative of the public official."
The definition of family in the same law includes sons-in-law, which appears to make Kushner ineligible for an official job. But there's no law against a president turning to a trusted friend or family member for advice or to convey sensitive messages to political allies.
Kushner, who owns the Observer newspaper, may also be planning to build a pro-Trump media empire, reportedly talking with industry experts about what it would take to set up "Trump TV" or a similar platform. While many assumed Trump TV would only get launched if the candidate lost, it's entirely possible Kushner will end up moving forward anyway.
As Christie, among others, has discovered the hard way, it's a mistake to ignore or underestimate one of the youngest and savviest political players on Team Trump.