Trump fired Comey in 2017, early in the Republican president's first term in office.
He has since regularly assailed Comey's handling of the FBI investigation that detailed contacts between Russians and Trump's 2016 campaign.
Since Trump returned to office in January, his Justice Department has been examining Comey's 2020 testimony before the Senate Judiciary Committee when he addressed Republican criticisms of the Russia investigation and denied that he had authorised disclosures of sensitive information to the news media.
The case against Comey, who served as FBI director from 2013 until 2017, marked the starkest example of the Trump administration using its law enforcement power against a prominent critic after the president promised retribution during his successful 2024 election campaign.
The grand jury's indictment came after the president mentioned Comey by name in a social media post chiding Trump-appointed US Attorney General Pam Bondi for not moving quickly enough to bring criminal charges against his most prominent antagonists, writing "JUSTICE MUST BE SERVED, NOW."
"No one is above the law," Bondi said in a post on X shortly after the news broke.
Without specifically mentioning Comey, Bondi added: "Today's indictment reflects this Department of Justice's commitment to holding those who abuse positions of power accountable for misleading the American people. We will follow the facts in this case."
The effort to target Comey has been viewed with scepticism in the Eastern District of Virginia, the US attorney's office handling the case.
The district's top federal prosecutor, Erik Siebert, resigned last week after drawing Trump's wrath for expressing doubts about the strength of the case, and the No.2 official, Mary "Maggie" Cleary, has also expressed concerns, according to people familiar with the situation.
Some other prosecutors in the office have told Siebert's successor, Lindsey Halligan, that charges should not be filed due to lack of evidence, according to one of the sources.
Trump and Comey have had an acrimonious relationship since the start of the president's first term in 2017. Trump fired him as FBI director days after Comey publicly confirmed that the president was under investigation over his election campaign's connections to Russia.
Comey then emerged as a prominent critic of the president, calling him "morally unfit" for office.
Comey's firing led to the appointment of another former FBI chief, Robert Mueller, being appointed as a special counsel to take charge of the Russia probe, which unearthed numerous contacts between the campaign and Russian officials but concluded that there was not enough evidence to establish a criminal conspiracy.
Trump repeatedly attacked the investigation as a "witch hunt," and his second administration has sought to undermine conclusions by US intelligence and law enforcement agencies about Russian interference in the 2016 presidential election in which Trump defeated Democratic rival Hillary Clinton.
A Justice Department internal watchdog found evidence of numerous errors but no political bias concerning the FBI's opening of the investigation. Republicans have long claimed that the investigation was intended to undermine Trump's first administration.
The Justice Department's internal watchdog in a 2019 report faulted Comey for asking a friend to give memos detailing Comey's one-on-one interactions with Trump to the New York Times.
The Justice Department during Trump's first term declined to pursue criminal charges against Comey.
