Piercy, 40, was among three players inside the top 60 in this week's Official World Golf Rankings added to the field. The No. 59-ranked Piercy joins Andrew Putnam (No. 50) and Emiliano Grillo (No. 53).
Piercy was a runner-up at the 2016 U.S. Open at Oakmont.
Bernd Weisberger will make his fifth tournament appearance as the top alternate from the qualifier held in England. Joel Dahmen will make his U.S. Open debut after finishing second at the Wells Fargo Championship.
The final spot went to Harris English, who is making his first major appearance since the 2017 U.S. Open at Erin Hills.
The 2019 U.S. Open begins Thursday and runs through Sunday. Brooks Koepka could join Willie Anderson as the only players to win three consecutive U.S. Opens. Anderson accomplished the feat from 1903 to 1905.