The lawsuit, filed just after 3 p.m. in the U.S. District Court for the Eastern District of Kentucky, claims that CNN "elevated false, heinous accusations of racist conduct" against Sandmann and failed to adhere to "well-established journalistic standards and ethics."
Sandmann and his family previously announced they were filing a lawsuit against The Washington Post for $250 million in compensatory and punitive damages after the paper’s coverage of an encounter that went viral on social media.
Co-counsel for Sandmann, Todd McMurtry, in an exclusive appearance on Fox News' "The Story" Tuesday, said that his client's "character has now been determined by the lies issued by CNN" following their widespread coverage of Sandmann.
"What CNN's tagline is, is, 'facts first,' and what we believe their reporting was in this circumstance was, 'lies first, cover up second,' and facts not yet determined by that organization," McMurtry said.
The attorney said that what the news network reported was "without any reasonable investigation, they took something straight off Twitter that had been in essence manipulated so that it told one story and they reported it as the truth."
Sandmann, a junior at Covington Catholic High School in Kentucky, became a target for outrage after a video of him standing face-to-face with a Native American man, Nathan Phillips, while wearing a red Make America Great Again hat surfaced in January.
The 16-year-old was one of a group of students from Covington attending the anti-abortion March for Life in Washington, D.C., while Phillips was attending the Indigenous Peoples' March on the same day.
Sandmann and the Covington students were initially accused of initiating the confrontation, but other videos and the students' own statements showed that they were verbally accosted by a group of black street preachers who were shouting insults at them and the Native Americans. Sandmann and Phillips have both said they were trying to defuse the situation.
McMurtry said they're also "looking very closely" at reporting on the story from NBC, The Associated Press, HBO "for the conduct of Bill Maher," as well as individual people, like Kathy Griffin "who sent out these horrible tweets that are called doxxing."
Fox News' Liam Quinn and Brian Tully contributed to this report.