[2] In November 2021, de Meester scored on his senior team debut for Viktoria Köln in a 5–1 away win against SSV Bornheim in the second round of the 2021–22 Middle Rhine Cup.
Liga debut in a 2–1 away defeat against Borussia Dortmund II, coming in as a substitute, replacing Michael Schultz in the 90th minute.
He came in as a second-half substitute, replacing Thomas Idel, scoring Viktoria's second goal of the match in the 91st minute.
[citation needed] In March 2024, de Meester was reportedly one of the players being recruited by head coach Tom Saintfiet and team manager Freddy Gonzalez to play for the Philippines.
A month later, de Meester was visited by the Belgian coach himself on one of his scouting trips in Europe.