As a youth, St. Louis played for Laraza FC of the U.S. Virgin Islands Premier League for nine years.
In 2019 St. Louis traveled to Spain with three other USVI youth players to trial with the academies of seven professional clubs.
[4] However, he eventually transferred and joined international teammate Joshua Ramos on the Dalton States Roadrunners.
He made fifteen appearances that season[7] St. Louis represented the USVI at the youth level in the 2018 CONCACAF U-20 Championship.
[8][9] He made his senior international debut on October 12, 2019, in a 2019–20 CONCACAF Nations League C match against Barbados.