The former Texas congressman posted a photo after the debate with three of the players who attended.
"Honored to have Michael, Matthew, and RoJe from Lansing with me tonight. They bravely took a knee so their fellow Americans could stand a little more free," he wrote.
O’Rourke reached out to the former Lansing Catholic High School football players Michael Lynn III, Matthew Abdullah and RoJe Williams and spoke with them by phone last week. Teammate Kabbash Richards is away at college and was unable to attend the debate.
O’Rourke, whose defense of NFL players who chose to take a knee to protest police brutality and racism went viral in 2018, learned of the men’s story and found them through “general local outreach,” his campaign said.
In a statement to The Associated Press on Monday, O’Rourke said the four “have served their community in one of the most American ways possible.”
Meanwhile, candidate Rep. Tim Ryan also stood out Tuesday as the only candidate who didn't put his hand on his heart during a performance of "The Star-Spangled Banner" at the opening of the event, prompting a backlash on social media.
Ryan, D-Ohio, stood alongside South Bend Mayor Pete Buttigieg, Vermont Sen. Bernie Sanders, Massachusetts Sen. Elizabeth Warren, former Texas Rep. Beto O’Rourke, Minnesota Sen. Amy Klobuchar, author Marianne Williamson, former Maryland Rep. John Delaney, former Colorado Gov. John Hickenlooper and Montana Gov. Steve Bullock.
As the national anthem played, Ryan was the only candidate to stand with his hands clasped in front of his body, rather than at his chest.
Fox News' Gregg Re and the Associated Press contributed to this report.