Arnaldo A. Mignucci-Giannoni was born on October 31, 1961 in San Juan, Puerto Rico.

He received a B.A. in Political Science and Philosophy from the University of Rhode Island, a J.D. magna cum laude from Catholic University of Puerto Rico, School of Law in 1987 , and a Masters in Law from Harvard University School of Law in 1993.

While at Catholic University School of Law, he was a member of the Catholic University Law Review from 1985 to 1987 and its Chief Editor from 1986 to 1987. He was a founding member of the Delta Theta Phi Law Fraternity, Juan R. Torruella Chapter, and received the Puerto Rico Bar Association Award for graduating with the highest academic average.