TOKYO — Before Athing Mu introduced herself to the world at the Tokyo Games, the public-address announcer at Olympic Stadium butchered her name.

It was Friday, before her opening round heat of the women’s 800 meters, and Mu did not hide her dismay.

“I’m sure everyone saw my face,” said Mu, a 19-year-old American whose name is pronounced “Ah-THING Moe.”

“I don’t even know what he said, but it was terrible. Like, where do you even get that from?”

Mu said all this with a charming, disarming smile — she was used to people getting her name wrong, she said, but it also seemed clear that she wanted some respect. So she went out and made sure to earn it as an Olympic gold medalist.

On Tuesday, Mu became the first American to win gold in her event since 1968, the latest and greatest milestone for one of the sport’s rising stars.

Mu, who is from Trenton, N.J., finished in 1 minute 55.21 seconds, her personal best and an American record. Her strategy from the start was clear: go to the front and stay there. Her commanding pace turned the race into a coronation.

Keely Hodgkinson of Britain was second, and Raevyn Rogers, Mu’s American teammate, finished third for the bronze.

Mu arrived in Tokyo a few weeks after she completed a historic freshman year at Texas A&M, where she broke a host of collegiate records and won the N.C.A.A. title in the 400. At the end of June, she announced she was going pro and signed with Nike.

She proceeded to dominate the 800 meters at the U.S. trials, winning a spot in Tokyo by running the fastest time in the world this year. The fastest time, that is, until today.