Throughout her career, Esther has been a champion of the rights of all workers — regardless of where they come from or where they were born. To help provide hope to immigrant workers, Esther launched a groundbreaking program to ensure eligible UFCW members were first in line to apply for citizenship. Prior to that, she spearheaded the Union Citizenship Action Network, also known as UCAN, to help UFCW members become naturalized and get on the path to citizenship. Esther was the lead staff person on the UFCW Commission on ICE Enforcement that highlighted civil rights abuses in the 2006 Swift raids. All along, Esther has never lost focus on the broader goal of giving aspiring Americans the chance to become citizens and ensuring all workers and their families are protected from exploitation.

Esther served as the director of UFCW's Civil Rights and Community Action Department for 10 years. In that role, she helped put UFCW on the front lines of the most crucial civil rights battles of our time—fighting back against voter suppression, working to end the exploitation of refugees from countries like Burma, Sudan, and Somalia, creating more opportunities for women and expanding LGBTQ equality. In 2016 Esther became the first Latina appointed to the position of International Secretary-Treasurer for the United Food & Commercial Workers (UFCW), the largest private-sector union in the country with over 1.3 million members.

Prior to her career at the UFCW, López played an active role in improving labor conditions within the state of Illinois, serving as Deputy Chief of Staff for Labor, as well as in the governor’s cabinet as Director of the Illinois Department of Labor. Esther also spent a couple of years with the National AFL-CIO. She retired in 2019 from the UFCW, and now resides in New Mexico with her partner Antonio.