Brey-Casiano earned a master's degree in library science from University of Illinois.
Brey-Casiano earned a PhD from University of Texas at Austin's Graduate School of Library & Information Science.
In 2001, Brey-Casiano stood up against the Texas Ranger, mayor of El Paso, Texas, a lawyer named Francisco Domínguez, and the El Paso police for the purpose of protecting intellectual freedom and privacy of library users.
In September 2017, as the Regional Public Engagement Specialist, Brey-Casiano was an opening ceremony speaker at the Argentine Binational Center Executive Directors Meeting in Argentina.
[5] Brey served 2018–21 as director of the Office of American Spaces (OAS) in Washington, D.C., overseeing more than 600 of public diplomacy platforms in over 145 countries In 2022 she was appointed director of the Quality of Life Department by the city of Las Cruces, New Mexico.