Xinis was born in Mineola, New York, graduated from the University of Virginia and went to Yale Law School. She clerked for Judge Diana Gribbon Motz on the 4th U.S. Circuit Court of Appeals. She was an assistant federal public defender in Maryland and adjunct professor at the University of Maryland Francis King Carey School of Law.

Federal Judge Paula Xinis is at the center of the case of a Maryland man mistakenly deported to El Salvador by the Trump administration that has emerged as a critical test of Trump’s aggressive crackdown on immigration in the United States.

A judge put a weeklong pause on collecting information in Kilmar Abrego Garcia's deportation case after the Trump administration asked her to.