The man, Erich Nikischer, had worked at his job for almost 30 years.
“I waited until the national anthem ended, I took off my shirt, threw my Bills hat on the ground, walked out,” Nikischer told WGRZ.
Nikischer said he doesn't mind players protesting, but that the national anthem is the wrong time to demonstrate.
“During the national anthem…the song that is about our country, our veterans that fight and die for us, it's just something I feel you shouldn't disrespect that way,” he said. "I believe people have the right to protest; I just don't believe that's the proper venue for it.”
Several players from the Bills and the opposing Denver Broncos took a knee during the anthem at New Era Field on Sunday after President Donald Trump criticized NFL players who protest Friday. Trump said owners should "fire" NFL players who protest the anthem and referred to them as "son of a b----."
Bills owners Terry and Kim Pegula released a statement saying the team met to discuss the remarks, and they called Trump's words "divisive and disrespectful."
The Bills and Broncos were among a throng of teams and players to protest, with over 200 individuals protesting and three full teams boycotting the anthem. Nikischer said he would never go New Era Field again and he would not watch another NFL game until the protests end.
Colin Kaepernick, currently a free agent, protested police brutality and racial inequality by kneeling during the national anthem last season, but this weekend's protests were the largest mass demonstration so far.