Haarvi was born in 2372 on Trill. His life was uninteresting. His ambition in life was to be a host to a symbiote. He was washed out of the program. He joined Starfleet to get away from Trill and his failed dream.
Haarvi Pux grew up like a normal Trill. His sole ambition in life was to become host to a symbiote. When he was washed out of the symbiote program, he had no more drive, so he joined Starfleet.