Who is Jack Smith, the special counsel behind the Trump classified documents indictment?

Special counsel Jack Smith's monthslong investigation into Donald Trump's alleged mishandling of classified documents has entered a new chapter with the indictment of the former president.

Trump faces 37 felony counts, which include charges relating to the willful retention of national defense information, according to the indictment unsealed Friday. Walt Nauta, an aide to the former president, has also been indicted in the investigation, according to the document released Friday.

The Justice Department's move marks the first time a former president has faced federal charges.

"Our laws that protect national defense information are critical to the safety and security of the United States, and they must be enforced," Smith said at a news conference Friday. "Violations of those laws put our country at risk."

"Adherence to the rule of law is a bedrock principle of the Department of Justice and our nation's commitment to the rule of law sets an example for the world," he added. "We have one set of laws in this country and they apply to everyone."

Jim Trusty - the former president's attorney who was removed from the case Friday morning and subsequently resigned from the legal team entirely - had told CNN Thursday evening that Trump is facing a charge under the Espionage Act, along with charges of obstruction of justice, destruction or falsification of records, conspiracy and false statements.

The former president has been ordered to appear at a federal courthouse in Miami on Tuesday. Smith said Friday that his office will seek a speedy trial.

Appointed by Attorney General Merrick Garland, Smith was tasked in November to look into whether Trump or his aides committed crimes by taking classified documents to his Mar-a-Lago resort after he left the White House and whether they obstructed the investigation. The probe had escalated in recent weeks with several high-profile interviews and a former White House official telling prosecutors that Trump knew the proper process for declassifying documents and followed it correctly at times while in office, undercutting Trump's claims that he automatically declassified everything he took with him to Mar-a-Lago. Earlier this week, CNN reported that the Justice Department informed the former president's legal team that he is a target in the probe - such notification is often a strong sign that an indictment could follow.

Trump has denied wrongdoing. He and his right-wing allies have slammed the probe as partisan and a weaponization of the federal government.

"The corrupt Biden Administration has informed my attorneys that I have been Indicted, seemingly over the Boxes Hoax," Trump wrote on Truth Social.

Smith, who is also overseeing the DOJ's investigation into efforts to overturn the 2020 election, however, has investigated members of both parties, handling some of the most high-profile political corruption cases in recent memory - to mixed outcomes.

The special counsel's experience ranges from prosecuting a sitting US senator to bringing cases against gang members who were ultimately convicted of murdering New York City police officers. His career spans multiple stints in the Justice Department and international courts, which until his appointment had allowed him to keep a relatively low-profile in the oftentimes brassy legal industry.

After serving as a prosecutor at the local and federal levels as well as a stint at the International Criminal Court, Smith oversaw corruption cases as chief of the Justice Department's public integrity unit from 2010 to 2015.

Smith was the head of the section when the department failed to convict former senator and vice-presidential candidate John Edwards, a Democrat, in a corruption case in 2012 and when then-Virginia Gov. Bob McDonnell, a Republican, was indicted in 2014. He also oversaw the investigation into former House Majority Leader Tom DeLay, a Republican, closing the probe in 2010 without bringing charges.

Smith would go on to serve as an assistant US attorney for the Middle District of Tennessee, taking over as acting US attorney in early 2017. He became vice president of litigation for the Hospital Corporation of America later that year.

In recent years, Smith lived outside of the United States as the chief prosecutor for the special court in The Hague, a role he assumed in 2018 in which he investigated war crimes in Kosovo.

This story has been updated with additional information.

CNN's Zachary Cohen, Kara Scannell, Jeremy Herb, Katelyn Polantz, Chandelis Duster, Marshall Cohen, Kaitlan Collins, Paula Reid, Sara Murray, Kristen Holmes, Tierney Sneed, and Evan Perez contributed to this report.