STORY: The move follows the mass shooting in Uvalde, Texas, in which 19 children and two teachers were killed.
"We mean business. We are resolved in this fight. We're not giving up. We're not giving into the cynicism. We're going to turn this around," Newsom said at a news briefing.
Newsom hit out at the U.S. federal judges who overturned some of California's strictest gun laws. In June last year, federal judge Roger Benitez overturned California's 32-year-old ban on assault weapons, describing it as a "failed experiment".
He also criticized Texas governor Greg Abbott for saying in a news conference earlier on Wednesday that "evil swept across Uvalde yesterday."
"Look at the rhetoric that you heard today about evil and mental health as if evil doesn't exist and persist around the globe, mental health is not an issue in every part of the globe. What's unique in the United States is this savagery because the availability, ease and access of weapons of war, weapons of war that are manufactured," Newsom said.
According to the Giffords Law Center to Prevent Gun Violence, some 36,000 Americans or more die by firearms every year, or about 100 a day.
The United States leads high-income countries in gun violence, accounting for 9% of all firearm homicides globally even with 4% of the world's population, while also possessing more civilian-owned guns - 393 million - than any comparable nation, the Giffords Law Center said.