Picault earned two caps with the U.S. men's national team, debuting under Jurgen Klinsmann, in an international friendly in 2016. His second appearance came under interim head coach Dave Sarachan in 2018.
In 2023, he used his one-time switch to represent the Haiti national team to compete in the CONCACAF Gold Cup. His grandfather, Henry, was a former professional - and was an ex-captain of the Haiti national team.
Since switching over to Les Grenadiers, Picault has recorded 14 appearances on the international stage.