The rally was held simultaneously with Gov. Jerry Brown's press conference in Sacramento, which was designed to kick off the campaign to pass the measure which would impose higher tax rates for high income earners and raises California's sales tax from 7.25 percent to 7.5 percent.
The rally was the first time that the governor's Yes On Prop. 30 organization and the Reclaim California's Future organization have held a joint event.
The Reclaim California group includes California Calls, The California Partnership, Inland Congregations United for Change and the California Faculty Association.
The city of San Bernardino was selected for this historic rally because traditionally this county has among the lowest voting rates in the state for its young adults, said Maribel Nunez of the California Partnership.
Registering those non-voting young adults will become a major focus for Reclaim California's Future, she said.
Without Proposition 30, California's public schools face an additional $6 billion in cuts this year, coalition officials say.
Natalia Cortes, a senior at SBHS, has already seen local school cuts abolish the art history class she wanted to take and now the possibility of there being school plays this year is in doubt.
Cortes, who was among several speakers during the rally, has participated in several plays every year during her first three years at SBHS.
Funding for the teacher to work additional hours on plays isn't likely, she said.
And as state college tuition fees soar, Cortes said her dream of attending the University of California, Berkeley is fading.
She's got a full ride scholarship to a school in Mississippi and may end up going there.
After college, her vision - since eighth grade - of becoming a schoolteacher in California is also becoming less likely because so many teaching jobs are being eliminated.
Cuts at San Bernardino Valley College have already impacted Javier Hernandez, 22, a business major.
Hernandez plans to take calculus to help him grapple with sophisticated business alternatives, but this semester he couldn't get an algebra class he needs to build his foundation for higher math.
Steven Herrera, 24, a chemical engineering senior at University of California, Riverside, said he's able to secure the classes he needs for his specialized major, but as he seeks to broaden his knowledge into other fields, he frequently can't snag the class he wants.
"This (Proposition 30) shouldn't be looked at as a tax. It's an effort to reclaim California's greatness," he said.