In the following months, Guo quickly met and trained with other young players in Atlanta, including the nationally-ranked Maxwell Feng and Justin Zhou.

[5] In July 2014, Guo won the gold medal for Team USA in the Pan American Youth (U8) in Oaxtaepec, Morelos, Mexico.

[7][8] In July 2016, Guo became the gold medalist in the Pan American Youth Chess Championship (U12) with an 8/9 score in Montevideo, Uruguay.

On June 24, 2018, at the age of 12 years, one month and five days, Guo earned the International Master title by scoring 7/9 and tying for the first at the Pan American Junior (U20) Chess Championship in Guayaquil, Ecuador.

[12] In November 2018, Guo tied for second in the World Cadets Chess Championship (U12) in Santiago de Compostela, Spain.

[13] In June 2021, Guo won the National Open at the age of 15 in Las Vegas ahead of Grandmasters Illia Nyzhnyk, Andrew Hong, Emilio Córdova, and Lázaro Bruzón due to having the best tiebreaker results.

[28] Two weeks later he broke the 2500 FIDE rating and achieved his fourth GM norm with a 6.5/9 score at the SPARKASSEN CHESS TROPHY 2023 in Dortmund, Germany.