The president told reporters about his decision at Joint Base Andrews Tuesday afternoon.
Kerik was sentenced to 48 months in prison in 2010 after pleading guilty on multiple charges of tax fraud and lying to officials.
He served as Rudy Giuliani's body guard during Giuliani's 1993 mayoral campaign and was later appointed by Giuliani to serve as the New York City police commissioner in 2000.
He was nominated by President George W. Bush to be the secretary of Homeland Security but withdrew his nomination due to potential tax violations.
Kerik was released from prison in 2013 after serving three years for good behavior.
In recent years he's been a frequent defender of President Trump's on Fox News.
On Tuesday, Kerik thanked the President on Twitter.
President Trump on Tuesday also commuted the 14-year prison sentence of former Illinois Gov. Rod Blagojevich who was convicted of political corruption and also pardoned former San Francisco 49ers owner Edward DeBartolo Jr. who was convicted in a gambling fraud scandal.
The President was asked if he planned on pardoning his confidant Roger Stone on his conviction for witness tampering and lying to Congress.
"I haven't given it any thought," the President said. "In the meantime he's going through a process, but I think he's being treated unfairly."
“I haven’t given it any thought … but I think he’s been treated very unfairly,” President Trump says when asked if he has considered pardoning Roger Stone. https://t.co/CUCpL7GghX pic.twitter.com/TX1QNbfwaI— ABC News (@ABC) February 18, 2020