But the illustration -- which has been adopted by sports fans, civil rights activists and celebrities -- comes from an unlikely artist.
Khalid Albaih, a Romania-born Sudanese artist living in Qatar, is renowned throughout the Middle East for addressing controversial political and social issues, including government corruption, the war in Yemen and the Israeli-Palestinian conflict.
However, his Kaepernick cartoon tackles a far more distant issue: American civil liberties.
Kaepernick, a former quarterback for the San Francisco 49ers, sparked a national conversation during the 2016 NFL football season when he refused to stand for the national anthem. Instead, the footballer knelt in protest of police shootings of African-American men and other social injustices faced by black people in the United States.
"To me, this is something that has to change," Kaepernick said in an August 2016 interview. "And when there's significant change and I feel like that flag represents what it's supposed to represent and this country is representing people the way that it's supposed to, I'll stand."
Albaih originally published the cartoon in September 2016, when he was a human rights fellow teaching at Colby College in Maine.
With his cartoon of Kaepernick, Albaih said he wanted to evoke the historic images of other African-American athletes who took a firm position on civil liberties.
"The minute I saw (Kaepernick kneeling), it just reminded me of the image of (John) Carlos and (Tommie) Smith with their fists up in the '68 Olympics
," Albaih said, referring to an iconic moment when the two black athletes gave a black power salute during the US national anthem.
"It was the 'black fist' of our time," Albaih said. "I had to make that connection."
"People just wanted (black athletes) to do their sports, clap at them and leave," he said. "They don't want them to do anything serious, to be anything but that sports person."
Kaepernick's protest attracted widespread support and criticism. He is currently a free agent, and has yet to land on an NFL team's roster for the 2017 season.
Last month, demonstrators gathered in support of Kaepernick
at NFL headquarters in New York. Among the groups represented at the rally was the NAACP, which has suggested
Kaepernick's unemployment is the result of "retaliatory actions"
by the NFL against the quarterback.
Other athletes have joined Kaepernick's protest
, including Denver Broncos linebacker Brandon Marshall and Miami Dolphins wide receiver Kenny Stills. Seattle Reign FC soccer star Megan Rapinoe also showed solidarity by taking a knee during the national anthem.
The protest has also inspired student athletes and their coaches to kneel in protest
Albaih became interested in the American civil rights movement in 2016 when he was invited to tour the United States with his artist collective for a documentary commissioned by The Guardian.
The Middle Eastern artists took a road trip across the country, visiting the South and landmarks of the civil rights movement.
Albaih said the experience made him realize that whether someone is living in the United States, Qatar or Syria, "at the end of the day, we're all just asking for basic human rights, to be considered as people."
Milton "MD" Dodson, a clothier in Atlanta, persuaded Albaih to let him print the cartoon on T-shirts.
Dodson said he gave shirts to Chance the Rapper and Dave Chappelle, who have been seen wearing the shirt. Dodson also handed them out to NAACP staff and supporters at last month's rally at NFL headquarters.
Snoop Dogg has even posted a picture of the shirt on Instagram
According to Dodson, Albaih saw an early version of the T-shirt last year, but was surprised when he started seeing photos of celebrities wearing it.
Still, Albaih is no stranger to having his cartoons -- or "khartoons
," as he calls them (a play on Khartoum, the capital of Sudan) -- go viral. The designs he posts on social media often take on lives of their own.
And the Kaepernick cartoon isn't the first time he's weighed in on US issues. He often satirizes President Donald Trump.
Albaih said he believes it's important to comment on US affairs because "nothing is local anymore. Everything is global."
"Whatever Trump says in America will affect me in Africa, or affect me in Qatar," Albaih said.
"It's something that people need to understand. Everything is connected now. Everybody's connected now."