Received his Bachelor of Arts from Boston College and his Juris Doctor, magna cum laude, from the University of Puerto Rico School of Law.

In 1995, he joined McConnell Valdés, where he maintained a diverse commercial litigation practice that focused on contracts, products liability, personal injury, antitrust and maritime disputes and accumulated substantial jury trial and appellate experience in complex matters.

In 2011, 2013 and 2016, Arias-Marxuach served as an adjunct professor teaching various courses at the Interamerican University of Puerto Rico School of Law.

[3] Arias-Marxuach was recommended for a federal judgeship by Resident Commissioner of Puerto Rico Jenniffer González.

[14] He became chief judge on October 19, 2021, after Gelpí was elevated to the United States Court of Appeals for the First Circuit.

[15] On November 13, 2020, President Trump announced his intent to nominate Arias-Marxuach to a seat on the United States Court of Appeals for the First Circuit.

President Trump nominated Arias-Marxuach to the seat vacated by Judge Juan R. Torruella, who died on October 26, 2020.