“I definitely want to save the money and invest it toward my future,” Kyle said. “Make sure I’m safe with the money.”

He does plan to splurge on a new desk, he said.

Kyle finished the tournament with 59 points. Harrison Chang , 24, an Orange County, Calif., native who plays as “Psalm,” came in second place with 33 points and won $1.8 million, according to Fortnite Intel. The message pinned to the top of his Twitter account reads, “There is no freaking way I just made 1.8 million ...”

After the competition, he ran around excitedly for 10 minutes. “I went crazy,” Mr. Chang said Monday. He became a full-time gamer in 2016 when he dropped out of the University of California, Los Angeles. In total, he has 19 years of gaming experience.

Mr. Chang, who currently lives with family and plans to move out soon, isn’t sure what he’ll do with his winnings. “I’ve always lived kind of frugally and I’m not really big into, like, spending big,” he said. “I’ll use it somehow to make more money, though.”

Third place went to 16-year-old Shane Cotton of Redondo Beach, Calif., who goes by “Epikwhale” and finished with 32 points. It was his first major competition and he won $1.2 million. He brushed it off on Twitter as “a couple of $.”

[What exactly is Fortnite? Here’s our non-gamer’s guide.]

Shane practiced six to eight hours a day during the school year, and in the summer he stepped it up to around 10 hours a day, he said. “It’s a great relief for me,” he said about his performance at the World Cup. “I’ve been putting in hours every day. Just trying to get better and prepared for this tournament.” He plans to save most of his winnings, but said he will spend some on clothes and shoes.