Every evening for two weeks, Nick Johnson walked nearly 13 kilometres around New York City in search of elusive Pokemon, and it seems his persistence and late nights paid off.

The Brooklyn man now believes he’s the first person to catch all 142 Pokemon available in the North American version of the wildly popular Pokemon Go game.

Johnson, 28, has been a fan of Pokemon games since childhood, when he played Pokemon Red and Blue on his Nintendo Game Boy.

“So when Pokemon Go came out, it felt natural to pick up where I left off,” Johnson told CTV News Channel on Monday from California, where he’s attending a wedding.

He spent hours after work trying to catch the virtual monsters, sometimes with his girlfriend, who he says was “really supportive” of his quest. Each evening, he walked as many as eight hours at a time. At one point, he even called an Uber driver to take him to New Jersey to search for one of the pieces of his collection.

The more Johnson caught, the more he realized he really might be able to “catch ‘em all,” as the Pokemon tagline goes.

“I didn’t really think I had a chance at this until I got to 135. At that point, I said, ‘Why not; just go for it.’ And so there were a couple of nights there I was out pretty late at the end,” he said.

All that walking offered an expected benefit: Johnson estimates he lost between 8 and 10 pounds.

While Johnson has caught them all in North America, he now has a chance to build his collection even further. He has partnered with Marriott Rewards and will soon travel to Europe, Australia and Japan to catch rare Pokemon that are only available in those regions.

As for what got him addicted to Pokemon Go, Johnson says it was probably a bit of nostalgia for his video-game-playing childhood.

“The ability to fulfill my childhood dreams of being a Pokemon master, that got me pretty good,” he said.