Arrigoitia earned a Bachelor of Arts degree in history from the UPR, where she was also a magna cum laude student, with the highest GPA in her academic concentration.

[2] For a short period of time, Arrigoitia taught humanities in the University of Puerto Rico before she proceeded to study law, earning her Juris Doctor degree.

[2] She practiced with the law firm of Hartzell, Ydrach, Mellado, Santiago before deciding to attend Fordham University in New York City to pursue a doctorate degree in history.

It was later published by the Institute of Puerto Rican Culture, titled José de Diego, el Legislador.

In the late 1990s, Arrigoitia became interested in writing a book about Antonio Rafael Barceló, first president of the Puerto Rican Senate.

[1][7] Arrigoitia also worked on a book about the women who have served in the Puerto Rican Legislature, as requested by the former President of the Chamber of Representatives, Jennifer Gonzalez.

[1] On April 5, she was also featured in the section Vidas Unicas in El Nuevo Dia, another local newspaper, and in a piece titled Exploradora del Genio Patrio (Explorer of the Patriotic Genre).