Gissel is originally from Puerto Rico and is fluent in Spanish. She has been practicing law in the New Orleans metro area since 2004. After working as an Assistant District Attorney for Orleans Parish and as an Associate at a local insurance defense firm, she joined her husband, Oskar Pérez, in 2011 and founded Ferriol Pérez, LLC, a Hispanic-owned, full service law firm specializing in client-focused legal representation for the local community.

Gissel has a bachelor's degree in Psychology and Classics from the University of Arizona, and a law degree, with a Certificate in International Law, from Loyola University School of Law. She was an active member of Loyola's Moot Court Staff and graduated in the top 15% of her law school class.

Gissel is also a local author and is on the Board of the Japan Society of New Orleans.