Espinosa worked as the Deputy Director for the Labor Council for Latin American Advancement (LCLAA) after earning his associate degree from 2007 to 2008. As Deputy Director, he liaised between the organization and its collaborators, including coalitions, agencies, and legislative bodies. Additional responsibilities included directing daily operations, expanding programming, including workshops and training, and working closely with the Executive Director to administer the organization's policies, goals, and objectives. While at the University of Phoenix, he served as the National Director of Special Projects with the League of United Latin American Citizens from 2008 to 2009. At the organization, he was responsible for executing the 2008 and 2009 LULAC National Conventions, which saw over 15,000 participants in various workshops, seminars, and events and revenues from sponsorships. He also oversaw the organization's Presidential Appointments Project during the 2008 Presidential transition and developed and maintained partnerships with key partners. He expanded the organization's engagement with Congress on public policy, drafting materials on behalf of the organization.

Espinosa joined the Hispanic Federation in 2009 as their National Director of Advocacy. Critical achievements with the organization include managing the National Hispanic Leadership Agenda, which is a coalition for the 30 leading Hispanic organizations in the country, implementing the Latinos United for Healthcare Campaign, developing the Federation's policy and advocacy efforts, expanding the Hispanic Federation's exposure to public policy priorities, and developing the first-ever Hispanic Federation Public Policy Agenda, with priorities covering health, housing, education, immigration, civic participation, energy, and the environment. He served in the role for three years before briefly working as a Senior Legislative Assistant at the U.S. House of Representatives in 2013.

In 2013, Espinosa joined Earthjustice as a Legislative Representative, drawing on his experiences and expertise in public policy. He focused on the Clean Water Act and its jurisdictional issues at Earthjustice. Espinosa is a founding member of GreenLatinos, a national non-profit that connects Latino leaders dedicated to addressing national, regional, and local environmental, natural resources, and conservation issues affecting the health and well-being of the Latino community in the U.S. He served on the organization's board from 2013 to 2015 in addition to serving as Executive Vice President and Chief Operating Officer from 2016 to 2017.

He left GreenLatinos to work at the House Committee on Natural Resources as their Director of Outreach and Engagement in 2017, where he worked for almost five and a half years before starting his current position at Earthjustice in 2023. At the House Committee, he helped advance outreach and engagement efforts to various stakeholders. Among his many achievements at the House, he led the development of an inclusive community-led stakeholder process that set the foundations for the Environmental Justice for All Act passed by Chair Grijalva (AZ) and late Representative McEachin (VA). He also helped the same legislators organize the Congressional Convening on Environmental Justice, a historic event that brought environmental justice participants nationwide.

Espinosa returned to Earthjustice after seven years to serve as their Legislative Director for Climate and Energy. In addition to his diverse range of work experiences, Espinosa has served on boards, councils, and advisory committees. In addition to serving on the GreenLatinos board, he was previously a Hispanic Council on Federal Employment member in the U.S. Office of Personnel Management and the Diversity & Inclusion Advisory Committee at the Chesapeake Bay Trust. He has also used his expertise to spread awareness of environmental issues through publications for the Huffington Post and Latino Rebels. Adding to his already extensive skillset, Espinosa holds licenses and certifications from the Montgomery County Fire and Rescue Service, the Joint Center for Political and Economic Studies, NAUI Worldwide, and a Private Pilot Certification from the Federal Aviation Administration.