David Ainuʻu was born in American Samoa[3][4] on 20 November 1999.[2] Ainuʻu was first introduced to rugby when he was the water boy for his brother's team.[5] He first played rugby himself with Prairie RFC in Yelm, Washington.[5] Ainuʻu was also selected to play for the Washington Loggers, Rugby Washington's state-level representative side.[5] Ainuʻu attended Capital High School in Olympia, Washington.[6]
Club career
Prior to December 2017, Ainuʻu played rugby for Seattle Saracens in the CDI Premier League.[5] In December 2017, Ainuʻu signed a six-month academy contract with Toulouse in France's Top14.[4] (Ainuʻu had previously agreed to join the Seattle Seawolves for Major League Rugby's inaugural 2018 season, but ended that agreement before the season began in order to play at the higher-level of competition.)[7] In September 2018, Ainuʻu re-signed with Toulouse, committing to the club through the 2020–21 season.[8] Ainuʻu made his Top 14 debut for Toulouse on 23 September 2018, appearing as a halftime-substitute in a 66–15 defeat to Montpellier.[9][10]
Ainuʻu was first named to the roster of the United States senior national team ahead of the 2018 June rugby union tests,[11] but did not make an appearance for the team at that time, instead playing for the Junior All-Americans.[8] Ainuʻu made his debut for the Eagles on 10 November 2018, appearing as a substitute, in the Eagles' 30–29 victory over Samoa during the 2018 end-of-year tests.[12] Ainuʻu made his first appearance in the Eagles' starting lineup on 2 March 2019 in a 32–25 defeat to Uruguay during the 2019 Americas Rugby Championship.[13]