President-elect Trump is expected to pick Stephen Miller as deputy chief of staff for policy in his administration.
Vice President-elect JD Vance posted a message of congratulations to Miller on X Monday morning.
"This is another fantastic pick by the president," Vance wrote, following a CNN report about Trump's pick.
Miller was a senior adviser in Trump’s first term. He helped craft many of Trump’s hard-line speeches and plans on immigration.
VANCE CONGRATULATES MILLER ON NEW TRUMP ADMINISTRATION POSITION
Since Trump left office, Miller has served as the president of America First Legal, an organization of former Trump advisers fashioned as a conservative version of the American Civil Liberties Union, challenging the Biden administration, media companies, universities and others over issues such as freedom of speech and religion and national security.
Miller has advocated for mass deportations during a second Trump term. He spoke at Trump's massive rally at Madison Square Garden in New York City.
FORMER ICE DIRECTOR TOM HOMAN 'HONORED' TO BE APPOINTED TRUMP'S BORDER CZAR: 'WE HAVE TO FIX IT'
"I want you to think for a minute about the decades of abuse that has been heaped upon the good people of this nation, their jobs looted and stolen from them and shipped to Mexico, Asia and foreign countries, the lives of their loved ones ripped away from them by illegal aliens, criminal gangs and thugs who don't belong in this country," Miller told the packed Manhattan venue. "A political system that punishes working citizens, oppresses them at every turn, takes away the rights of free speech, the right to political expression, the right to fundamental safety in their own country. One man dared to step forward nine years ago and say enough, no more. America gets its future back."
Miller spoke of the indictments and lawsuits Trump has faced, adding that the former president "took a bullet for democracy" – a reference to the assassination attempt against Trump in Butler, Pa.
He also spoke of high profile cases of illegal immigrant suspects being charged with the rape and murder of women and girls.
"He was fighting for your children, for your wives, your husbands, everyone that you love and know in the world the right to live in a country where criminal gangs cannot just cross our border and rape and murder with impunity," Miller said of Trump. "Think about how corrupt and hateful and evil a system is that allows gangs to come into this country and rape and murder little girls."
CLICK HERE TO GET THE FOX NEWS APP
"Who's going to stand up for our daughters? Who's going to stand up for the girls of America, the women of America, the families of America? Who's going to stand up and say, the cartels are gone, the criminal migrants are gone. The gangs are gone. America is for Americans and Americans only," Miller added.
The Associated Press contributed to this report. This is a developing story. Check back for updates.