The first officer of the Nadesico, Jun has no small infatuation for Yurika, leaving a position in the Earth's military to join her crew and "look out for her". She is clueless of how he feels and considers him her "best friend", though the rest of the crew realize his feelings.
A common running gag is Jun's misunderstanding of Yurika's special efforts, such as preparing food--he believes it is for him, but it always ends up being for Akito, with him being passed by.