After earning his master's degree, Sunia worked as a Congressional staffer to U.S. Representative Mervyn Dymally of California.
[2] He returned to American Samoa in 1997, joining the territory's attorney general office.
[6] On January 4, 2019, United States Secretary of the Interior David Bernhardt appointed Sunia as the associate justice of the High Court of American Samoa.
His uncle, Tauese Sunia, was the fifth elected Governor of American Samoa.
Sunia carries the matai title of Muagutitia in Pu'apu'a, Samoa.