The ad said, "Believe in something, even if it means sacrificing everything."
He sold the Nike inventory at his Colorado sporting goods and memorabilia store, Prime Time Sports, and made national news as the shopkeeper boycotted the biggest sporting goods name.
Martin knew the Nike boycott would hurt.
"Being a sports store without Nike is like a petrol station without gas," he said.
This week, Martin announced that Prime Time Sports will be closed in the coming days.
"It was never about ownership, it was about principle," Martin said Wednesday evening while he was in his shop, preparing to shut him down.
Martin said the boycott was about the principle of profit. Although the loss of revenue played a role in his decision to close the store, he was absolutely glad he had.
"You are not trampling on the men who granted Colin Kaepernick and me the right to freedom of expression," he said.
In 20 years in the business, Martin said he does not consider himself an activist as a man who sells jerseys. He had never boycotted anything before, even though he had canceled an autograph appearance of Brandon Marshall in 2016, after the Denver Broncos player had knee-kicked during a national anthem before a game.
This week, he decided to tell his nine employees that it was time to call it a career. Everything in the store is 40% off.
Other shops in the mall, including a Sears, close. Mall traffic has failed.
The store is open until everything is gone, he told KOAA.
"I did not give in to big Nike and big bucks, I did not give in. I did it my way," he told the station in Colorado Springs.