Vice President Mike Pence swore in the former chairman of the Republican National Committee.
Kelly was named chief of staff in July 2017.
The former FBI director mentioned the crowd-size kerfuffle as an example of Trump lying in private as well as in public.
There have been several high-profile departures from the Trump administration in the year since the president took office.
“The last thing I wanted to do was walk away from one of the great honors of my life," Kelly said about his position at the Department of Homeland Security.
A revolving door never spun so fast.
The end of 2017 is the perfect opportunity to look back and remember those we loved and lost from the Trump administration over the past 12 months.
Plus: His surprisingly warm reception from Mattis, his troubles with McMaster, why he's comfortable profiting off wars, and finally some details on that shady Russian connection.
Plus: The three times he spoke with Trump about a potential Moscow deal.
In response to a fake Reince Priebus, Anthony Scaramucci told him to read Othello.
"Keep pushing this crap & I’ll start dropping oppo on you.”
"I will speak with Gen. Kelly and the president about that."
Remember Michael Flynn?