Matosantos was arrested in downtown Sacramento early Friday morning after California Highway Patrol officers saw her car weaving down the street. Also, CHP officials said Matosantos' vehicle registration was expired.
After she was pulled over, an officer observed signs of intoxication and asked Matosantos to perform a field sobriety test. The results were not immediately available.
Matosantos apparently told the officer that she had been at a downtown restaurant.
In a statement, Matosantos called her decision to get behind the wheel "reckless and irresponsible."
A spokesperson for Gov. Jerry Brown said Matosantos offered her resignation, but the governor rejected it.
Matosantos has been state finance director since 2009.
The Associated Press contributed to this report.