Upon completing his clerkship in Fall 1991, he joined the Miami law firm of Steel, Hector & Davis where he remained for three years.

Ferrer then returned to public service, first as a White House Fellow and Special Assistant to the Secretary of the U.S. Department of Housing and Urban Development (HUD), and later as Deputy Chief of Staff and Counsel to then Attorney General Janet Reno.

After five years at the Department of Justice, Ferrer returned to Miami in 2000 to become an Assistant United States Attorney.

As an Assistant United States Attorney, he handled and tried numerous high-profile matters, including international money laundering, health care fraud, narcotics, international human rights abuses, immigration and firearms offenses.

In addition, he received the Attorney General's Medal in 2000, and Superior Performance and Special Merit Awards for his work as an Assistant U.S.