On Sunday at the Ariake Gymnastics Centre, Skinner, 24, finished second behind Brazil's Rebeca Andrade in the women's gymnastics vault final. Bronze went to Korea's Seojeong Yeo.
As Skinner competed, she was cheered on in the stands by the men and women's U.S. gymnasts, including Simone Biles, Jordan Chiles and Grace McCallum.
The American spectators in the arena roared after her second-place finish.
"I am so proud of her!" Skinner's coach Lisa Spini tells PEOPLE. "It's very difficult to go first and then just have to sit back and wait. There is also no touch warm up on the competition equipment in event finals."
"She was persistent and mentally strong," Spini says.
Skinner's mom, Kym, celebrated her daughter's Olympic accomplishment at a watch party early that morning back in the States. "We are so happy for MyKayla. I still can't believe it! So surreal! We are so blessed to be her parents," Kym tells PEOPLE. "I am truly inspired by her. She has experienced so much disappointment and even had a flight home the next evening after finals. She thought she was retired and then the call came; she had to refocus and start training again. So amazed that she was able to stay focused and vault her way to the silver medal. What an epic ending to an amazing journey!"
Skinner, who was selected as an individual and not as a member of the U.S. team — which was instead made up of Biles, Chiles, Sunisa Lee and McCallum — originally did not qualify for any event final after competing on all four apparatuses during Sunday's preliminary round.
She finished in 10th place in the all-around rankings with a total score of 55.398.
But on Saturday, USA Gymnastics announced that Biles would withdraw from the vault final — in the wake of issues with her air awareness and mental health pressures — and that Skinner would replace the 24-year-old veteran captain of the U.S. women's gymnastics roster.
Laurence Griffiths/Getty Images
"[Biles] will continue to be evaluated daily to determine whether to compete in the finals for floor exercise and balance beam," gymnastics officials said of the change. "MyKayla Skinner, who had the fourth-highest score in vault during qualifications, will compete in vault finals for the U.S. alongside Jade Carey, who finished with the second-highest score."
After the announcement was made, Skinner shared her excitement on Instagram as well as her support for Biles, a close friend.
"Looks like I get to put a competition Leo on just one more time. Can't wait to compete in vault finals," the Arizona native wrote. "Doing this for us @simonebiles ❤️ It's go time baby!"
Jamie Squire/Getty Simone Biles and MyKayla Skinner
For Skinner, who is the oldest on the U.S. women's roster, taking home an Olympic medal almost didn't happen.
After not qualifying, she said her elite gymnastics career was effectively over.
"Heart broken 💔 but feeling sooo humbled and blessed for the amazing performance I had tonight! You have all brought me to tears thanks for being my biggest cheerleaders!" she wrote on social media at the time.
Not long before officials said Skinner would step in for Biles on vault, Skinner's mom spoke with PEOPLE about her daughter's dream of the podium.
"Simone must feel crushed that she can't compete. But it opened up that opportunity for MyKayla," Kym Skinner said. "MyKayla would just be on top of the world because she really wants a chance to get a medal."
To learn more about Team USA, visit TeamUSA.org. Watch the Tokyo Olympics now on NBC.