Downs, 21, was a standout performer for FC Koln during the 2024-25 campaign, scoring 11 goals in 32 matches across all competitions as he helped them secure promotion from the 2. Bundesliga to the first division in Germany.
In May, he received his first call-up to the U.S. men's national team and made his debut off the bench against Switzerland in an international friendly on June 10. He logged 28 minutes off the bench against Saudi Arabia in the USMNT's Gold Cup opener, becoming cap-tied to the program.
In total, Downs appeared in five of the six matches for the USA at the Gold Cup, and in the quarterfinals against Costa Rica, he scored the game-winning penalty in a shootout after a 2-2 regulation draw between the two teams.
“Damion is a player we have been monitoring for some time who possesses excellent physical qualities and the ability to disrupt defenses," said Johannes Spors, Southampton technical director. “Strengthening our attacking options was one of our top priorities this summer, and Damion is a player who will add real quality to the group. Despite his relatively young age, he is already a senior international, so we are excited to see him thrive in the environment here at Southampton.”