The league said Fournette violated its unsportsmanlike conduct and unnecessary roughness rules and, as a result, will miss Sunday's game against the Indianapolis Colts at TIAA Bank Field.
Monday's announcement did not mention any discipline for Lawson, who was also ejected after the incident in Buffalo's 24-21 win. Lawson told reporters on Tuesday that he expects to receive a fine, which he will appeal.
Fournette appealed his discipline, and the hearing will be Tuesday with appeals officer James Thrash, a source told ESPN's Adam Schefter.
"Sportsmanship is the cornerstone of the game and the league will not tolerate game-related misconduct that conveys a lack of respect for the game itself and those involved in it," NFL vice president Jon Runyan wrote in a letter to Fournette.
"Video of the incident shows that you were not a participant in the play and that you ran from your sideline to the opposite side of the field to insert yourself as an active participant in a fight. Once you entered the fight area, you struck a member of the opposing team. Your actions adversely reflected on the NFL and have no place in the game."
Jaguars coach Doug Marrone said earlier Monday that he spoke with Fournette and other players on Monday about the fight, which happened late in the third quarter.
"Those discussions are private, and we discussed all the personal fouls with the team," Marrone said. "We have 22 personal fouls, which leads the league. It is something that stops us from having the opportunity to win football games. I addressed it with the team and addressed it with some players individually."
Fournette is one of the Jaguars' three offensive captains, and none of them will play against the Colts. Center Brandon Linder is out for the year with a knee injury, and Marrone benched quarterback Blake Bortles for backup Cody Kessler.
Marrone also said he wasn't considering stripping Fournette of his captaincy because of the fight and punishment.
"Captaincy is voted by the team," Marrone said. "If the team came to me and said they wanted to strip his captaincy, then that is a team decision, not necessarily just the head coach's decision."
Fournette said after the game that he regretted leaving the Jaguars' sideline to get involved in a skirmish that started when teammate Dede Westbrook pushed Bills safety Micah Hyde. Fournette said he got angry when he saw Lawson shove teammate Carlos Hyde, and that's when he threw a punch at Lawson.
"You are going to have to rise up and also protect your own," Fournette said. "At the same time, you can't have that. I apologize to all the kids who look up to me and their parents. The biggest thing is this loss [is] totally on me. I take [full responsibility]."
Lawson and Fournette also had to be separated as they exited through the Bills' lone tunnel at the same time. While Fournette walked into the tunnel, a fan in the front row made contact with him, and Fournette briefly confronted that fan. A nearby police officer intervened.
"My biggest thing was when the fan hit me. I had a problem with that," Fournette said. "[Lawson] was saying what he had to say. I really don't care. Words are just words. They don't mean nothing to me. Just got to move on."
Buffalo coach Sean McDermott said he spoke with Lawson after the incident but would not discipline him.
Lawson told reporters Tuesday he was simply defending himself.
"At the time, how the whole situation happened, I was defending myself because he came from the sideline. So at that time, I was basically defending myself and my team, fighting for my brothers. Ain't nobody going to let anybody in this world let a man throw a punch at you and you won't react to it," he said, according to the Buffalo News.