"The president has accepted the recommendation of the Attorney General and the deputy Attorney General regarding the dismissal of the director of the Federal Bureau of Investigation," White House Press Secretary Sean Spicer said in a statement on Tuesday.
In a letter to Comey, the US president said, "It is essential that we find new leadership for the FBI that restores public trust and confidence in its vital law enforcement mission."
It was not immediately clear exactly why Comey was ousted.
"The FBI is one of our Nation's most cherished and respected institutions and today will mark a new beginning for our crown jewel of law enforcement," Trump said in the letter.
The dismissal takes place in the middle of an investigation in Russia’s alleged meddling of the US presidential elections in 2016. Moscow has repeatedly denied allegations of interfering in US elections.
The FBI as well as the US Senate and House intelligence committees have been investigating Russia's alleged meddling in the 2016 US presidential election and any possible ties between Trump’s associates and Moscow.
Comey was appointed FBI director by former President Barack Obama in 2013 to a 10-year term.
Top Republicans, including US Senate Majority leader Mitch McConnell, have called for the swift appointment of a new FBI director, saying the role was critical to counter national security threats.
"Once the Senate receives a nomination, we look forward to a full, fair and timely confirmation process to fill the director position," he said. "This is a critical role that is especially important as America faces serious threats at home and abroad.
US Senator John McCain said he was "disappointed” by the move and regretted the termination of Comey's tenure as the FBI director.