At the age of 15, after earning his brevet and being accepted into the Mont-Blanc Committee, Germain decided to move to the United States to attend high school.

[2] He made his international debut in February 2018 at the Youth World Championships in Otepää, but he failed to achieve notable results that year or the next, primarily due to poor shooting performances.

The American first drew attention at the 2020 Youth World Championships when he won the bronze medal in the sprint, finishing behind Alexei Kovalev and Ondřej Mánek.

Back in the World Cup in Ruhpolding, Germain achieved an impressive result, securing seventh place in the men's relay alongside Paul Schommer, Sean Doherty, and Jake Brown.

[4] Germain won his third international medal at the 2023 Junior World Championships, finishing third in the sprint behind his training partner Campbell Wright and Jan Guńka.