Today, there's backlash. Some football fans and Nike customers wish he didn't.
People who disapproved of Nike's campaign posted their outrage on social media. Some doused their Nike apparel and shoes with lighter fluid and set them on fire.
Their message: boycott Nike.
On Wednesday, Hillsborough Police asked its followers on Facebook to donate their Nike's rather than destroying them.
UNC student Ryan Branagan supports Kaepernick's campaign.
"Usually, people burning their own things they bought, generally is not how a boycott works," Branagan said.
The company and protesters are inserting themselves into a firestorm debate around the American flag, racial equity and policing.
Branagan said he supports Kaepernick and athletes taking a knee during the national anthem and using any platform including Nike to address inequality.
"When they start talking about police brutality, then you inevitably have a white backlash," Branagan said. "And I think that's what the Nike boycott is about."
Jessie Hayes, of Columbus County, disagreed with Branagan.
"I see the Black Lives Matter side, but I also see it from the Blue Lives Matter side, too," Hayes said. "I feel like there's better ways to do it than kneel."
Hayes and her wife are not surprised by the boycott.
They wish Nike had chosen a military veteran instead. They consider Kaepernick's sitting and kneeling to the American flag and national anthem inexcusable.
"To disgrace something that covers the whole country and not just him, I feel like they (Nike) could pick somebody else." Hayes said. "Someone who is actually a hero. Not someone who just knelt because he wanted to."
Duke and UNC athletics use Nike products and apparel.
Asked about the campaign, UNC said the controversy has "no impact on our partnership with Nike."
Duke said, "any questions regarding Nike advertising campaigns should be referred directly to Nike."