Oropeza graduated from Alhambra High School in 1975 and went on to earn a bachelor's degree in Business Administration from California State University, Long Beach.

She began her career in public service as the first Latina student body president, and the first to serve two terms, at California State University, Long Beach.

Oropeza was the first Latina to serve as a member of the Long Beach Unified School District Board of Education and held office from 1988 to 1994.

In 2005, the League of California Cities' Latino Caucus named her Legislator of the Year[citation needed]; in 2006, the Los Angeles League of Conservation Voters awarded her the Smith-Weiss Environmental Champion Award for her work on issues from air pollution and cancer prevention to radiation and environmental advocacy.

As a tribute to Oropeza's dedication to fostering protections for key California-state public health programs, the Los Angeles County Affiliate of Susan G. Komen for the Cure, in joint collaboration with the six other California-based Komen Affiliates ("the California Collaborative"), established the Senator Jenny Oropeza Public Policy Internship position.

The Senator Jenny Oropeza Memorial Scholarship was established after her death, and is awarded annually at California State University, Long Beach to a student who is committed to a career in public service.

During her time on the Long Beach City Council, Jenny fought hard to develop and name the park in honor of labor leader and civil rights activist Cesar Chavez.

In August 2012, in recognition of Oropeza's work to find the necessary funds to finance completion of a critical section of the Alameda Corridor project that had run out of money, the California Legislature approved the naming of the Honorable Jenny Oropeza Memorial Overcrossing for the section of Pacific Coast Highway in Wilmington that created the bridge that spans the Alameda Corridor.

Oropeza successfully worked with Federal, State and local government entities, as well as the railroads and Metropolitan Transportation Authority to find the funds to construct this last and critical portion of the project.

Oropeza, who died in 2010 at age 53, was the first Latina to serve on the Long Beach USD school board and the city council.