In a statement, press secretary Sarah Sanders said, "Today, President Donald J. Trump issued an Executive Grant of Clemency (Full Pardon) to Dinesh D’Souza, an accomplished author, lecturer, and scholar.
"Mr. D’Souza was, in the President’s opinion, a victim of selective prosecution for violations of campaign finance laws. Mr. D’Souza accepted responsibility for his actions, and also completed community service by teaching English to citizens and immigrants seeking citizenship.
In light of these facts, the President has determined that Mr. D’Souza is fully worthy of this pardon," Sanders said.
Tweeting out the news of the pardon earlier Thursday, the president said that D'Souza had been treated "very unfairly by our government."
Later in the day, the president expanded on his tweet in comments to reporters aboard Air Force One on a trip to Texas,, saying “I’ve always felt he was very unfairly treated, and a lot of people did, a lot of people did."
The president expressed his belief that D'Souza should have just received "a quick minor fine, like everybody else with the election stuff" and said "what they did to him was horrible.”
D’Souza tweeted his thanks to the president a few hours after the news broke.
Trump, who said he doesn't personally know D'Souza beyond a phone conversation he had with him last night to tell him he was receiving a pardon, said D’Souza "almost had a heart attack” when he called with the news.
Trump told reporters he is also considering commuting the sentence of former Illinois Gov. Rod Blagojevich, a Democrat, as well as a pardon for businesswoman and tv personality Martha Stewart.
In the case of Blagojevich, the president said he feels his sentence was too harsh for what he did.
"What he did does not justify 18 years in a jail," Trump said. "If you read his statement, it was a foolish statement there was a lot of bravado … but it does not .. plenty of other politicians have said a lot worse. And it doesn’t, he shouldn’t have been put in jail."
The president also noted that Blagojevich "was on The Apprentice for a short period of time."
He later said that Martha Stewart is among "others" he's considering pardons for, saying "to a certain extent Martha Stewart was harshly and unfairly treated" and noting that "she used to be my biggest fan in the world … before I became a politician. But that’s okay I don’t view it that way.”
His cause was taken up by some on the political right as an example of anti-conservative bias during the Obama administration.
White House spokesman Raj Shah denied that this pardon was an effort by Trump to send a message to political allies wrapped up in the Russia investigation.
“Each of the president’s actions on pardons or on other things should be judged on the merits, looking at the facts and circumstances surrounding that case,” Shah said. “The president felt it was merited.”
Asked why it was so necessary to pardon D’Souza, who pleaded guilty and expressed remorse to the judge who convicted him on campaign finance violations, Shah said D’Souza paid his fine and served his community service obligations.
Shah would not say whether Trump took the action based on any type of recommendation from the Department of Justice's pardon attorney, instead saying the president coordinated with the White House Counsel.
“He’s worked this process through the White House Counsel and felt that it was appropriate to pardon Dinesh D’Souza,” Shah said. “The president has the constitutional authority to do so,” Shah said.
When asked if the DOJ Office of the Pardon Attorney had reviewed D’Souza’s case, a Justice Department spokesperson told ABC News, “He doesn’t have a petition pending with the Office of the Pardon Attorney.”
Traditionally, pardon petitions are vetted by the pardon attorney before they land on the president’s desk.
However, the president has a sweeping pardon authority under the constitution and is free to exercise that authority as he wishes.
ABC News' Alex Mallin and Jack Date contributed to this report.