Haupeakui played football at College of San Mateo before picking up rugby, playing with Eagle Folau Niua at East Palo Alto prior to signing for PRO Rugby's inaugural Sacramento Express franchise. In his first professional season, he recorded three tries and earned an international call-up to John Mitchell's Eagles squad during the 2016 Summer Series. In the offseason, Haupeakui signed a two-year contract with Guinness Pro12 side Glasgow Warriors.