McKennie paid tribute to George Floyd during a Bundesliga match for former club Schalke as he wore an armband with the words "Justice For George." Floyd, who was Black, died in police custody in Minnesota in May after a white police officer kneeled on his neck for more than seven minutes. The killing sparked Black Lives Matter protests in cities across the United States.
The 22-year-old joined Serie A champions Juventus in the summer, but McKennie said he is not content with merely progressing on the field and wants to highlight the issues of racism that continue to affect so many people.
"This year, at the beginning of the season, we played and the fans after the game were making monkey noises at me," McKennie said in a video produced by Adidas. "It's devastating.
"I went back home to Dallas and I'm afraid to drive at night just because I don't know what's going to happen if I get pulled over. I'm representing a country that possibly doesn't even accept me just for the color of my skin.
"It's definitely a bit heartbreaking. When I wore the armband, I felt it was a duty and a responsibility: one being American and two being a Black American. I just felt a need to bring awareness overseas. I got a lot of support from it. I also got hate from it.
"'You're a soccer player, you shouldn't be making political statements,' and I'm just thinking in my head: 'I don't see how this is a political statement at all.'
"A person lost their life, I'm not going to shut up and dribble. I'm not going to make my opinions small just because people believe that I should just play soccer.
"I don't want to be just known as a great soccer player. I want to be known as a great human being, as a great person and that is what I am starting to try and do; to create my legacy. This version of me that I love."
Floyd's death came at a time when competitive sports were on hold worldwide due to the coronavirus pandemic. Germany's Bundesliga was the first to return to action, leading McKennie to be the first high-profile soccer player to pay tribute.
His gesture was followed by others: Borussia Monchengladbach's Marcus Thuram took a knee after scoring in their next match and Borussia Dortmund's Jadon Sancho wore a T-shirt with the words "Justice For George."
Since then, various tributes have been displayed around the world in solidarity with the Black Lives Matter movement, including in the Premier League, where players took a knee after kickoff before every game.