The Dallas Cowboys team, including owner Jerry Jones, knelt on the field before the national anthem was played during the Monday Night Football game against the Arizona Cardinals in Glendale, Arizona.
The demonstration was intended as a statement for equality and a representation of unity, according to ESPN's sideline reporter Lisa Salters.
During the national anthem, the teams, in separate locations on the field, both stood with arms linked or holding hands.
No member of either team was shown in the televised broadcast kneeling or sitting during the anthem. Neither team has ever had a player kneel during the anthem.
'Show of disrespect'
The latest chapter in the controversy came Friday night when Trump told those attending a political rally in Alabama that NFL owners should fire any "son of a bitch" who stages a protest during the national anthem.
The President's focus remained on sports Saturday morning, as he tweeted he was rescinding a White House invitation for the NBA champion Golden State Warriors because two-time league MVP Steph Curry was "hesitating" in accepting the presidential offer. (Curry actually had flat-out declined the invitation.)
Hours later, the President went back in on athletes following in the knee prints of Kaepernick, who has said he refuses to stand during the anthem because he cannot "show pride in a flag for a country that oppresses black people and people of color."
Read Trump's two-part tweet: "If a player wants the privilege of making millions of dollars in the NFL, or other leagues, he or she should not be allowed to disrespect our Great American Flag (or Country) and should stand for the National Anthem. If not, YOU'RE FIRED. Find something else to do!"
Trump went on to make the protests his cause du jour -- or more accurately, de deux jours -- as 15 of his next 23 tweets over the weekend addressed the demonstrations.
His stance gained traction among his base and some NFL fans, who took to social media to tell athletes to stick to sports and skip the politics. Others used hashtags such #standforouranthem and #standfortheflag, tweeting that they were going to follow Trump's advice to tune out.
NFL ratings have seen a modest decline in recent years, and the league finished at the bottom of a fan experience survey conducted by J.D. Power earlier this year. About 12% of those surveyed said they had watched fewer games than they had in previous years. Of those respondents, more than a quarter blamed the national anthem protests for their decline in viewership.
Ahead of the Sunday matchup between the Chicago Bears and Pittsburgh Steelers -- during which Steelers offensive lineman and ex-Army Ranger Alejandro Villanueva declined to stay in the locker room with his team during the anthem -- fans told CNN they disapproved of players kneeling.
"(It's a) show of disrespect, not only for those who have fought and died for our country but for those serving," Derek Zumbahlem said. "I disagree with it."
Bears fan Amit Sud, too, said he felt players should stand. "I do respect the players' rights to take the knee. However, Soldier Field has history," he said.
'That offends everybody'
Within the NFL there was a starkly different response, which was also reflected on social media and in some fan bases. Trump's criticism seemed to galvanize the league's players and coaches.
In some cases, team owners showed up on the sideline to lock arms with their players. Trump supporter Shad Khan, who owns the Jacksonville Jaguars, was one of them. Trump friend Robert Kraft stood in the owners box, hand over heart, before his New England Patriots played, but he said he was "deeply disappointed" in Trump's remarks.
New Orleans Saints quarterback Drew Brees called Trump's remarks "unbecoming of the office of the President," while Buffalo Bills running back LeSean McCoy said the President "is just acting like a jerk."
Miami Dolphins safety Mike Thomas asked, "You're the leader of the free world, and this is what you're talking about?"
The Seattle Seahawks and Tennessee Titans followed the Steelers' lead, staying in the locker room for the anthem. Most teams chose to lock arms in a show of unity, but even among those squads, some players opted to kneel. The Baltimore Ravens' Terrell Suggs and the Denver Broncos' Von Miller lent their considerable star power to the protests, kneeling along with dozens of others players.
"What you just saw was a variety of responses with the theme of unity," an NFL front office source said. "All across the league, owners, coaches and players came together to decide what was best for them. ... If Trump thought he could divide the NFL, he was wrong."
Sports commentator Bob Costas told CNN the response among players and coaches was "universal" and said, "There's almost no one in the NFL who wants to support or rationalize the tone or content of President Trump's remarks."
Asked why he felt Trump's words united the league when the protests have been going on for more than a year, Costas compared the President's remarks on the anthem protests to his words after white nationalists marched in Charlottesville, Virginia.
"Well, when you call people sons of bitches across the board, that offends everybody. White and black, they've stood shoulder to shoulder on those fields, in those locker rooms. What kind of a statement is that to make?" Costas said.
"And I don't think it's irrelevant that clearly the President had more passion and conviction for those remarks than he did -- when he finally got around after equivocating -- to distancing himself to some extent from white nationalists and neo-Nazis. He clearly had more fervor for this than for that."