An administrative staff member for the US team. Oliver has dreams of becoming an American U-17 representative himself someday despite not being very talented, but is pleasant and modest about it. He helps Ryoma buy time for the team by posing as Ryoga (just by wearing Ryoma's jacket) when the US team fails to show up on time for their exhibition match against the Tube Republic. Likely due his last minute call, Oliver initially lacks a lot of the mental strength necessary to play tennis competitively and falters a lot early on, but shows a surprising amount of determination to win later on. With Ryoma's subtle support, he was able to take at least one game before the two win their whole set.