In a statement, the network said that it does not condone Fox News talent participating in campaign events.
Ironically, Hannity had promised on Monday morning that he would only be interviewing Trump at the Missouri rally, writing, "I will not be on stage campaigning with the President".
'By the way, all those people in the back are fake news, ' Hannity told the crowd of Trump supporters, resulting in boos from the audience.
Fox News, with its conservative-leaning talk shows, some of which are unabashedly pro-Trump like Hannity's, has long had a unique relationship with the Trump administration. He was speaking before a frantic final day of campaigning that included rallies in Ohio, Indiana, and Missouri, where he was introduced by radio personality Rush Limbaugh.
"The one thing that has made and defined your presidency more than anything else", Hannity said, "promises made, promises kept".
However, in a TV interview on Monday, the U.S. leader said he wished he had taken a softer tone in his first two years as president.
But Trump called him to the stage after saying, "they're very special, they've done an incredible job for us".
"There's a woman on Saturday night who treats us very well", Trump said, praising Pirro's fiery opening monologues as "always brilliant".
Nasa to retire its planet-hunting Kepler space telescope
Scientists are expected to spend a decade or more in search of new discoveries in the treasure trove of data Kepler provided. In the year 2009, NASA has launched its Kepler Space Telescope whose main aim was to discover some few hundred exoplanets .
"There is something happening", Trump told Hannity and the millions watching at home. Pirro, a former NY state attorney general who has a weekend show on Fox, spoke after him.
Obama has taken on a more public role this fall after refraining from offering a full-blown counterpoint to Trump's policies, which have sought to dismantle Obama's legacy.
He clarified his remarks in a tweet on Tuesday, writing: 'To be clear, I was not referring to my journalist colleagues at FOX News in those remarks.
New claim: 'When POTUS invited me on stage to give remarks last night, I was surprised, yet honored by the president's request.
President Trump is holding his final midterm rally in Cape Girardeau, Missouri, just nine hours before the polls open in the state.
As shameless as that kind of partisan cheerleading is for a channel with "news" in its title, I would not be writing this column if that was all Hannity and Fox News did Monday.
Their appearances caused CNN to question Fox's credibility.
The latest incident wasnt the first time Fox News has had to chide Hannity for his closeness to the president.
Fox News draws a distinction between its opinion and news sides of the house.