Irving, 25, made the announcement as he filmed himself in a video on Instagram Live, less than a week after the league suspended him indefinitely for violating its substance-abuse policy for a third time in as many years.
"Basically, guys, I quit," Irving said. "I don't want to talk about a suspension and all this other nonsense. I'm outta there. I'm not doing this s--- no more."
Irving specified that his problem is with the league, rather than the sport.
"Everyone questions my commitment to football, but let's get it straight, here and now," he said. "I love football. ... I wouldn't be here without it. Don't get me wrong, I love football. However, I don't love the NFL. The NFL is not football, you need to understand that. What you all see us do, the game and s---, that's, what, 20 percent of all the real s--- we're doing."
Irving appeared to be smoking marijuana during the video and spoke about how he disagreed with the NFL's policy on the substance.
"It's funny, you know, some people: 'Oh, you're addicted to weed, you're addicted to this and that,'" he said. "I mean, s---, if I'm gonna be addicted to something, I'd rather be addicted to marijuana, which is medical -- it's a medicine; I do not consider it a drug -- rather than Xanax bars or the hydros or the seroquel and all that crazy s--- that they feed you.
"Like I said, it's not about smoking weed. How many NBA players you see getting in trouble about this? How many coaches you see getting in trouble about this? How many baseball players? How many UFC players getting in trouble?"
Irving will be a free agent when the league year begins next week, and the Cowboys have not expressed a desire to bring him back.
"I don't think I'm a bad guy for choosing this route. I stand up for what I believe in," he said. "It is bulls---. I'll 'Kaepernick' myself before they 'Kaepernick' my ass."