As a social advocate, Ruiz began working on  issues impacting minority groups during his college years. At Harvard, he was elected to the student council four years in a row. He worked on the issue of increasing minority faculty in tenured positions on a committee with the Dean of Harvard College.

Within his advocacy marketing firm, Ruiz has worked on a range of issues, from financial literacy to the elimination of health inequities.

Ruiz has also been an advocate for comprehensive immigration reform, universal healthcare, and regulations to curb the impact of sugary drinks on chronic disease, writing as a Contributor to CNN.com. His columns have appeared in major newspapers, including the Houston Chronicle and Philadelphia Inquirer.

Ruiz served on the Board of Directors of CSPI (Center for Science in the Public Interest). He also founded the Harvard College Equity, Diversity & Inclusion Fund. As a member of PEN America, he advocates for freedom of expression and against the banning of books.