The New Jersey senator said he would use executive orders to close "inhumane" detention facilities at the border, end for-profit prisons, bolster immigration courts and provide relief for those in the Deferred Action for Childhood Arrivals (DACA) program.
Booker said he would also order the Homeland Security Department to develop "a wide range" of alternatives to detention by partnering with community-based case management programs and have the department establish probable cause for asylum cases within 48 hours of a migrant's arrival.
He cited research that shows involving nonprofit management groups is "cheaper, more effective and more humane" than incarceration.
"When kids are being stripped away from their parents and held in cages, I will not wait for Congress to solve this crisis," he said. "On day one of my presidency, I will take immediate steps to end this administration's moral vandalism.
"Although there are limits on what we can do to reverse the damage that has already been done to the lives of thousands and to communities across our country, we can put an end to the horror, and turn the page to a new chapter of our history."
According to the Migration Policy Institute, for-profit prisons made up two-thirds of the bed available for illegal immigrants in 2015.
Booker did not offer a figure on how much his plan might cost.