He hails from one family in Brasilia, Brazil. Gui’s parents are former players of basketball. He began his pro-occupation with Minas in the NBB during the 2018-19 season, though he saw sparing playing time until 2020-21. During that season, he commenced 23 of 42 appearances and averaged 7.8 points, 5.2 rebounds, and 1.5 assists in 20.2 minutes.
Gui averaged 10.5 points, five rebounds, and 2.2 assists in 25.8 minutes, in 2021-22. He also has national team donations. During the 2019 FIBA South America U17 tournament in Chile, he assisted Brazil to secure a gold medal and scored 27 points against Argentina in the final.
During the 2022 FIBA AmeriCup qualification, Gui made his senior national team launch. Playing 4 games, he averaged 8.3 points, 5.8 rebounds, one assist, one steals, and one block in 20 minutes per game.
Santos was picked by the Golden State Warriors as the 55th overall pick in the 2022 NBA draft. He also joined the Warriors for the NBA Summer League 2022.